ARTICLE 23 ULTRASONIC STANDARDS

Transcription

1 ARTICLE 23 ULTRASONIC STANDARDS SA-388/SA-388M Standard Practice for Ultrasonic Examination of Heavy Steel Forgings (ASTM A 388/A 388M-86) SA-435/SA-435M Standard Specification for Straight-Beam Ultrasonic Examination of Steel Plates (ASTM A 435/A 435M-82) SA-577/SA-577M Standard Specification for Ultrasonic Angle-Beam Examination of Steel Plates (ASTM A 577/A 577M-86) SA-578/SA-578M Standard Specification for Straight-Beam Ultrasonic Examination of Plain and (ASTM A 578/A Clad Steel Plates for Special Applications M-92) SA-609/SA-609M Standard Practice for Castings, Carbon, Low-Alloy, and Martensitic Stainless Steel, (ASTM A 609/A Ultrasonic Examination Thereof M-86a) SA-745 Standard Practice for Ultrasonic Examination of Austenitic Steel Forgings (ASTM A 745/A 745M-86) SB-509 Specification for Supplementary Requirements for Nickel Alloy Plate for Nuclear (ASTM B ) Applications SB-510 Specification for Supplementary Requirements for Nickel Alloy Rod and Bar for (ASTM B ) Nuclear Applications SB-513 Specification for Supplementary Requirements for Nickel Alloy Seamless Pipe (ASTM B ) and Tube for Nuclear Applications

2 1998 SECTION V SB-548 Standard Method for Ultrasonic Inspection of Aluminum-Alloy Plate for Pressure (ASTM B ) Vessels SE-114 Recommended Practice for Ultrasonic Pulse-Echo Straight-Beam Testing by the Contact (ASTM E ) Method SE-213 Standard Practice for Ultrasonic Inspection of Metal Pipe and Tubing (ASTM E ) SE-214 Standard Practice for Immersed Ultrasonic Examination by the Reflection Method [ASTM E Using Pulsed Longitudinal Waves (1985)] SE-273 Standard Practice for Ultrasonic Examination of Longitudinal Welded (ASTM E ) Pipe and Tubing SE-797 Standard Practice for Measuring Thickness by Manual Ultrasonic Pulse-Echo Contact (ASTM E ) Method

3 SA-388/SA-388M ARTICLE 23 ULTRASONIC STANDARDS SA-388/SA-388M STANDARD PRACTICE FOR ULTRASONIC EXAMINATION OF HEAVY STEEL FORGINGS SA-388/SA-388M (Identical with ASTM Specification A 388/A 388M-86) 1. Scope 1.1 This practice covers the examination procedures for the contact, pulse-echo ultrasonic examination of heavy steel forgings by the straight and angle-beam techniques. 1.2 This practice is to be used whenever the inquiry, contract, order, or specification states that forgings are to be subject to ultrasonic examination in accordance with ASTM Practice A The values stated in either inch-pound or SI units are to be regarded as the standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the specification. 1.4 This specification and the applicable material specifications are expressed in both inch-pound units and SI units. However, unless the order specifies the applicable M specification designation (SI units), the material shall be furnished to inch-pound units. 1.5 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Referenced Documents 2.1 ASTM Standards: E 317 Practice for Evaluating Performance Characteristics of Ultrasonic Pulse-Echo Testing Systems Without the Use of Electronic Measurement Instruments E 428 Recommended Practice for Fabrication and Control of Steel Reference Blocks Used in Ultrasonic Inspection 2.2 Other Documents: American Society for Nondestructive Testing, Recommended Practice for Nondestructive Personnel Qualification and Certification SNT-TC-IA, Supplement C Ultrasonic Testing American National Standard, ANSI B46.1, Surface Texture 3. Ordering Information 3.1 When this practice is to be applied to an inquiry, contract, or order, the purchaser shall so state and shall also furnish the following information: Method of establishing the sensitivity in accordance with and (Vee or rectangular notch) The diameter and test metal distance of the flat-bottom hole and the material of the reference block in accordance with

4 SA-388/SA-388M 1998 SECTION V SA-388/SA-388M Quality level for the entire forging or portions thereof in accordance with 10.3, and Any options in accordance with 6.1, 6.2, and Apparatus 4.1 An ultrasonic, pulsed, reflection type of instrument shall be used for this examination. The system shall have a minimum capability for examining at frequencies from 1 to 5 MHz. On examining austenitic stainless forgings the system shall have the capabilities for examining at frequencies down to 0.4 MHz The ultrasonic instrument shall provide linear presentation (within 5%) for at least 75% of the screen height (sweep line to top of screen). The 5% linearity referred to is descriptive of the screen presentation of amplitude. Instrument linearity shall be verified in accordance with the intent of Recommended Practice E 317. Any set of blocks processed in accordance with Recommended Practices E 317 or E 428 may be used to establish the specified 5% instrument linearity The electronic apparatus shall contain an attenuator [accurate over its useful range to 10% ( 1 db) of the amplitude ratio] which will allow measurement of indications beyond the linear range of the instrument. 4.2 Search Units having a transducer with a maximum active area of 1 in. 2 [650 mm 2 ] with 3 / 4 in. [20 mm] minimum to 1 1 / 8 in. [30 mm] maximum dimensions shall be used for straight beam scanning (see 7.2); and search units equipped from 1 / 2 by 1 in. [13 by 25 mm] to 1 by 1 in. [25 by 25 mm] shall be used for angle-beam scanning (see 7.3) Transducers shall be utilized at their rated frequencies Other search units may be used for evaluating and pinpointing indications. 4.3 Couplants having good wetting characteristics such as SAE No. 20 or No. 30 motor oil, glycerin, pine oil, or water shall be used. Couplants may not be comparable to one another and the same couplant shall be used for calibration and examination. 4.4 Reference Blocks containing flat-bottom holes may be used for calibration of equipment in accordance with and may be used to establish recording levels for straight-beam examination when so specified by the order or contract. 5. Personnel Requirements 5.1 Personnel performing ultrasonic examinations in accordance with this practice shall be qualified to Recommended Practice SNT-TC-1A, Supplement C Ultrasonic Testing. 6. Preparation of Forging for Ultrasonic Examination 6.1 Unless otherwise specified in the order or contract, the forging shall be machined to provide cylindrical surfaces for radial examination in the case of round forgings; the ends of forgings shall be machined perpendicular to the axis of the forging for the axial examination. Faces of disk and rectangular forgings shall be machined flat and parallel to one another. 6.2 The surface roughness of exterior finishes shall not exceed 250 in. [6 m] unless otherwise shown on the forging drawing or stated in the order or the contract. 6.3 The surfaces of the forging to be examined shall be free of extraneous material such as loose scale, paint, dirt, etc. 7. Procedure 7.1 General: As far as practicable, subject the entire volume of the forging to ultrasonic examination. Because of radii at change of sections and other local configurations, it may be impossible to examine some sections of a forging Perform the ultrasonic examination after heat treatment for mechanical properties (exclusive of stressrelief treatments) but prior to drilling holes, cutting keyways, tapers, grooves, or machining sections to contour. If the configuration of the forging required for treatment for mechanical properties prohibits a subsequent complete examination of the forging, it shall be permissible to examine prior to treatment for mechanical properties. In such cases, reexamine the forging ultrasonically as completely as possible after heat treatment To assure complete coverage of the forging volume, index the search unit with at least 15% overlap with each pass Do not exceed a scanning rate of 6 in./s [150 mm/s]. 396

5 SA-388/SA-388M ARTICLE 23 ULTRASONIC STANDARDS SA-388/SA-388M If possible, scan all sections of forgings in two perpendicular directions Scan disk forgings using a straight beam from at least one flat face and radially from the circumference, whenever practicable Scan cylindrical sections and hollow forgings radially using a straight-beam technique. When practicable, also examine the forging in the axial direction In addition, examine hollow forgings by angle-beam technique from the outside diameter surface as required in In rechecking or reevaluation by manufacturer or purchaser use comparable equipment, search units, frequency, and couplant Forgings may be examined either stationary or while rotating in a lathe or on rollers. If not specified by the purchaser, either method may be used at the manufacturer s option. 7.2 Straight-Beam Examination For straight-beam examination use a nominal 2 1 / 4 -MHz search unit wherever practicable; however, 1 MHz is the preferred frequency for coarse grained austenitic materials and long testing distances. In many instances on examining coarse grained austenitic materials it may be necessary to use a frequency of 0.4 MHz. Other frequencies may be used if desirable for better resolution, penetrability, or detectability of flaws Establish the instrument sensitivity by either the back reflection or reference-block technique Back-Reflection Technique (Back-Reflection Calibration Applicable to Forgings with Parallel Entry and Back Surfaces) With the attenuator set at an appropriate level, for example 5 to 1 or 14 db, adjust the instrument controls to obtain a back reflection approximately 75% of the full-screen height from the opposite side of the forging. Scan the forging at the maximum amplification setting of the attenuator (attenuator set at 1 to 1). Carry out the evaluation of discontinuities with the gain control set at the reference level. Recalibration is required for significant changes in section thickness or diameter. NOTE 1 High sensitivity levels are not usually employed when inspecting austenitic steel forgings, due to attendant high level of noise or hash caused by coarse grain structure Reference-Block Calibration The test surface roughness on the calibration standard shall be comparable to but no better than the item to be exam- ined. Adjust the instrument controls to obtain the required signal amplitude from the flat-bottom hole in the specified reference block. Utilize the attenuator in order to set up on amplitudes larger than the vertical linearity of the instrument. In those cases, remove the attenuation prior to scanning the forging. NOTE 2 When flat-surfaced reference block calibration is specified, adjust the amplitude of indication from the reference block or blocks to compensate for examination surface curvature (an example is given in Appendix AI) Recalibration Any change in the search unit, couplant, instrument setting, or scanning speed from that used for calibration shall require recalibration. Perform a calibration check at least once every 8 h shift. When a loss of 15% or greater in the gain level is indicated, reestablish the required calibration and reexamine all of the material examined in the preceding calibration period. When an increase of 15% of greater in the gain level is indicated, reevaluate all recorded indications During the examination of the forging, monitor the back reflection for any significant reduction in amplitude. Reduction in back-reflection amplitude may indicate not only the presence of a discontinuity but also poor coupling of the search unit with the surface of the forging, nonparallel back-reflection surface, or local variations of attenuation in the forging. Recheck any areas causing loss of back reflection. 7.3 Angle-Beam Examination Rings and Hollow Forgings: Perform the examination from the circumference of rings and hollow forgings that have an axial length greater than 2 in. [50 mm] and an outside to inside diameter ratio of less that 2.0 to Use a 1 MHz, 45 angle-beam search unit unless thickness, OD/ID ratio, or other geometric configuration results in failure to achieve calibration. Other frequencies may be used if desirable for better resolution, penetrability, or detectability of flaws. For anglebeam inspection of hollow forgings up to 2.0 to 1 ratio, provide the transducer with a wedge or shoe that will result in the beam mode and angle required by the size and shape of the cross section under examination Calibrate the instrument for the angle-beam examination to obtain an indication amplitude of approximately 75% full-screen height from a rectangular or 60 V-notch on inside diameter (ID) in the axial direction and parallel to the axis of the forging. A separate calibration standard may be used; however, it 397

6 SA-388/SA-388M 1998 SECTION V SA-388/SA-388M shall have the same nominal composition, heat treatment, and thickness as the forging it represents. The test surface finish on the calibration standard shall be comparable but no better than the item to be examined. Where a group of identical forgings is made, one of these forgings may be used as the separate calibration standard. Cut the ID notch depth to 3% maximum of the thickness or 1 / 4 in. [6 mm], whichever is smaller, and its length approximately 1 in. [25 mm]. Thickness is defined as the thickness of the forging to be examined at the time of examination. At the same instrument setting obtain a reflection from a similar OD notch. Draw a line through the peaks of the first reflections obtained from the ID and OD notches. This shall be the amplitude reference line. It is preferable to have the notches in excess metal or test metal when possible. When the OD notch cannot be detected when examining the OD surface, perform the examination, when practicable (some ID s may be too small to permit examination), as indicated above from both the OD and ID surfaces utilizing the ID notch when inspecting from the OD, and the OD notch when inspecting from the ID. Curve wedges or shoes may be used when necessary and practicable Perform the examination by scanning over the entire surface area circumferentially in both the clockwise and counter-clockwise directions from the OD surface. Examine forgings, which cannot be examined axially using a straight beam, in both axial directions with an angle-beam search unit. For axial scanning, use rectangular or 60 deg. V-notches on the ID and OD for the calibration. These notches shall be perpendicular to the axis of the forging and the same dimensions as the axial notch. 8. Recording 8.1 Straight-Beam Examination Record the following indications as information for the purchaser. These recordable indications do not constitute a rejectable condition unless negotiated as such in the purchase order In the back-reflection technique, individual indications equal to or exceeding 10% of the back reflection from an adjacent area free from indications; in the reference-block technique, indications equal to or exceeding 100% of the reference amplitude An indication that is continuous on the same plane regardless of amplitude, and found over an area larger than twice the diameter of the search unit. The extent of such an indication shall be accurately measured along with variations in amplitudes of reflections Planar indications shall be considered continuous over a plane if they have a major axis greater than 1 in. [25 mm]. In recording these indications corrections must be made for beam divergence at the estimated flaw depth In the back-reflection technique, discontinuity indications equal to or exceeding 5% of the back reflection. In the reference- block technique, indications equal to or exceeding 50% of the reference amplitude providing that they travel, are continuous, or appear as clusters Traveling indications are herein defined as indications whose leading edge moves a distance equivalent to 1 in. [25 mm] or more of metal depth with movement of the search unit over the surface of the forging A cluster of indications is defined as five or more indications located in a volume representing a 2 in. [50 mm] or smaller cube in the forging Reduction in back reflection exceeding 20% of the original measured in increments of 10% Amplitudes of recordable indications in increments of 10%. 8.2 Angle-Beam Examination Record discontinuity indications equal to or exceeding 50% of the indication from the reference line. When an amplitude reference line cannot be generated, record discontinuity indications equal to or exceeding 50% of the reference notch. These recordable indications do not constitute a rejectable condition unless negotiated as such in the purchase order. 9. Report 9.1 The report shall include the following: All recordable indications (see Section 8) For the purpose of reporting the locations of recordable indications, a sketch shall be prepared showing the physical outline of the forging including dimensions of all areas not inspected due to geometric configuration, the purchaser s drawing number, the purchaser s order number, and the manufacturer s serial number, and the axial, radial, and circumferential distribution or recordable ultrasonic indications. 398

7 SA-388/SA-388M ARTICLE 23 ULTRASONIC STANDARDS SA-388/SA-388M The specification to which the examination was performed as well as the frequency used, method of setting sensitivity, type of instrument, surface finish, couplant, and search unit employed The inspector s signature and date examination performed. 10. Quality Levels 10.1 This practice is intended for application to forgings, with a wide variety of sizes, shapes, compositions, melting processes, and applications. It is, therefore, impracticable to specify an ultrasonic quality level which would be universally applicable to such a diversity of products. Ultrasonic acceptance or rejection criteria for individual forgings should be based on a realistic appraisal of service requirements and the quality that can normally be obtained in production of the particular type forging Heavy austenitic stainless steel forgings are more difficult to penetrate ultrasonically than similar carbon or low-alloy steel forgings. The degree of attenuation normally increases with section size; and the noise level, generally or in isolated areas, may become too great to permit detection of discrete indications. In most instances, this attenuation results from inherent coarse grained microstructure of these austenitic alloys. For these reasons, the methods and standards employed for ultrasonically examining carbon and low-alloy steel forgings may not be applicable to heavy austenitic steel forgings. In general, only straight beam inspecting using a back-reflection reference standard is used. Because of attenuation, use of flat-bottom hole reference standards or angle-beam examination of these grades is normally impracticable Acceptance quality levels shall be established between purchaser and manufacturer on the basis of one or more of the following criteria Straight-Beam Examination No indications larger than some percentage of the reference back reflection No indications equal to or larger than the indication received from the flat-bottom hole in a specified reference block or blocks No areas showing loss of back reflection larger than some percentage of the reference back reflection No indications per or coupled with some loss of resultant back reflection per Angle-Beam Examination No indications exceeding a stated percentage of the reflection from a reference notch or of the amplitude reference line Intelligent application of ultrasonic quality levels involves an understanding of the effects of many parameters on examination results. 399

8 SA-388/SA-388M 1998 SECTION V APPENDIXES SA-388/SA-388M (Nonmandatory Information) X1. TYPICAL TUNING LEVEL COMPENSATION FOR THE EFFECTS OF FORGING CURVATURE X1.1 The curve (Fig. X1) was determined for the following test conditions: Material Nickel-molybdenum-vanadium alloy steel (A 469, Class 4) Instrument Type UR Reflectoscope Search unit 1 1 / 2 in. [30 mm] diameter quartz Frequency 2 1 / 4 MHz Reference block ASTM No (aluminum) Reflection area of in. 2 [6.5 mm 2 ] in nickel-molybreference curve denum-vanadium alloy steel Surface finish 250 in. [6 m] max. roughness X1.2 To utilize curve, adjust reflectoscope sensitivity to obtain indicated ultrasonic response on ASTM No reference block for each diameter as shown. A response of 1 in. [25 mm] sweep-to-peak is used for flat surfaces. Use attenuator to obtain desired amplitude, but do testing at 1 to 1 setting. X2. INDICATION AMPLITUDE COMPENSATION FOR TEST DISTANCE VARIATIONS X2.1 The curve (Fig. X2) has been determined for the following test conditions: Material Nickel-molybdenum-vanadium alloy steel (Specification A 469, Class 4) Instrument Type UR Reflectoscope Search unit 1 1 / 2 in. [30 mm] diameter quartz Frequency 2 1 / 4 MHz Couplant No. 20 oil Reference block ASTM No (aluminum) Reflection area of in. 2 [6.5 mm 2 ] in nickel-molybreference curve denum-vanadium alloy steel Surface finish 250 in. max. roughness X2.2 To utilize curve, establish amplitude from ASTM reference block to coincide with values from Appendix XI. FIG. X1 TYPICAL COMPENSATION CURVE FOR EFFECTS OF FORGING CURVATURE FIG. X2 TYPICAL DISTANCE-AMPLITUDE CORRECTION CURVE 400

9 SA-435/SA-435M ARTICLE 23 ULTRASONIC STANDARDS SA-435/SA-435M STANDARD SPECIFICATION FOR STRAIGHT-BEAM ULTRASONIC EXAMINATION OF STEEL PLATES SA-435/SA-435M (Identical with ASTM A 435/A 435M-82) 1. Scope 1.1 This specification covers the procedure and acceptance standards for straight-beam, pulse-echo, ultrasonic examination of rolled fully killed carbon and alloy steel plates, 1 2 in. [12.5 mm] and over in thickness. It was developed to assure delivery of steel plates free of gross internal discontinuities such as pipe, ruptures, or laminations and is to be used whenever the inquiry, contract, order, or specification states that the plates are to be subjected to ultrasonic examination. 1.2 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents, therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the specification. 2. Apparatus 2.1 The manufacturer shall furnish suitable ultrasonic equipment and qualified personnel necessary for performing the test. The equipment shall be of the pulseecho straight beam type. The transducer is normally 1 to in. [25 to 30 mm] in diameter or 1 in [25 mm] square; however, any transducer having a minimum active area of 0.7 in. 2 [450 mm 2 ] may be used. The test shall be performed by one of the following methods: direct contact, immersion, or liquid column coupling. 2.2 Other search units may be used for evaluating and pinpointing indications. 3. Test Conditions 3.1 Conduct the examination in an area free of operations that interfere with proper functioning of the equipment. 3.2 Clean and smooth the plate surface sufficiently to maintain a reference back reflection from the opposite side of the plate at least 50% of the full scale during scanning. 3.3 The surface of plates inspected by this method may be expected to contain a residue of oil or rust or both. Any specified identification which is removed when grinding to achieve proper surface smoothness shall be restored. 4. Procedure 4.1 Ultrasonic examination shall be made on either major surface of the plate. Acceptance of defects in close proximity may require inspection from the second major surface. Plates ordered in the quenched and tempered condition shall be tested following heat treatment. 4.2 A nominal test frequency of MHz is recommended. Thickness, grain size, or microstructure of the material and nature of the equipment or method may require a higher or lower test frequency. However, frequencies less than 1 MHz may be used only on agreement with the purchaser. A clear, easily interpreted trace pattern should be produced during the examination. 401

10 SA-435/SA-435M 1998 SECTION V SA-435/SA-435M 4.3 Conduct the examination with a test frequency and instrument adjustment that will produce a minimum 50 to a maximum 75% of full scale reference back reflection from the opposite side of a sound area of the plate. While calibrating the instrument, sweep the crystal along the plate surface for a distance of at least 1T or 6 in. [150 mm], whichever is the greater, and note the position of the back reflection. A shift in location of the back reflection during calibration shall be cause for recalibration of the instrument. 4.4 Scanning shall be continuous along perpendicular grid lines on nominal 9-in. [225-mm] centers, or at the manufacturer s option, shall be continuous along parallel paths, transverse to the major plate axis, on nominal 4-in. [100-mm] centers, or shall be continuous along parallel paths parallel to the major plate axis, on 3-in [75-mm] or smaller centers. A suitable couplant such as water, soluble oil, or glycerin, shall be used. 4.5 Scanning lines shall be measured from the center or one corner of the plate. An additional path shall be scanned within 2 in. [50 mm] of all edges of the plate on the scanning surface. 4.6 Where grid scanning is performed and complete loss of back reflection accompanied by continuous indications is detected along a given grid line, the entire surface area of the squares adjacent to this indication shall be scanned continuously. Where parallel path scanning is performed and complete loss of back reflection accompanied by continuous indications is detected, the entire surface area of a 9 by 9-in. [225 by 225-mm] square centered on this indication shall be scanned continuously. The true boundaries where this condition exists shall be established in either method by the following technique: Move the transducer away from the center of the discontinuity until the heights of the back reflection and discontinuity indications are equal. Mark the plate at a point equivalent to the center of the transducer. Repeat the operation to establish the boundary. 5. Acceptance Standards 5.1 Any discontinuity indication causing a total loss of back reflection which cannot be contained within a circle, the diameter of which is 3 in. [75 mm] or one half of the plate thickness, whichever is greater, is unacceptable. 5.2 The manufacturer reserves the right to discuss rejectable ultrasonically tested plates with the purchaser with the object of possible repair of the ultrasonically indicated defect before rejection of the plate. 5.3 The purchaser s representative may witness the test. 6. Marking 6.1 Plates accepted in accordance with this specification shall be identified by stamping or stenciling UT 435 adjacent to marking required by the material specification. SUPPLEMENTARY REQUIREMENTS The following shall apply only if specified in the order: S1. Instead of the scanning procedure specified by 4.4 and 4.5, and as agreed upon between manufacturer and purchaser, 100% of one major plate surface shall be scanned. Scanning shall be continuous along parallel paths, transverse or parallel to the major plate axis, with not less than 10% overlap between each path. 402

11 SA-577/SA-577M ARTICLE 23 ULTRASONIC STANDARDS SA-577/SA-577M STANDARD SPECIFICATION FOR ULTRASONIC ANGLE-BEAM EXAMINATION OF STEEL PLATES SA-577/SA-577M (Identical with ASTM A 577/A 557M-86) 1. Scope 1.1 This specification covers an ultrasonic angle-beam procedure and acceptance standards for the detection of internal discontinuities not laminar in nature and of surface imperfections in a steel plate. This specification is intended for use only as a supplement to specifications which provide straight-beam ultrasonic examination. NOTE: An internal discontinuity that is laminar in nature is one whose principal plane is parallel to the principal plane of the plate. 1.2 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the specification. 2. Ordering Information 2.1 The inquiry and order shall indicate any additions to the provisions of this specification as prescribed in Examination Conditions 3.1 The examination shall be conducted in an area free of operations that interfere with proper performance of the examination. 3.2 The surface of the plate shall be conditioned as necessary to provide a clear, easily interpreted trace pattern on the screen. Any specified identification which is removed to achieve proper surface smoothness shall be restored. 4. Apparatus 4.1 The amplitude linearity shall be checked by positioning the transducer over the depth resolution notch in the IIW or similar block so that the signal from the notch is approximately 30% of the screen height, and the signal from one of the back surfaces is approximately 60% of the screen height (two times the height of the signal from the notch). A curve is then plotted showing the deviations from the above established 2:1 ratio that occurs as the amplitude of the signal from the notch is raised in increments of one scale division until the back reflection signal reaches full scale, and then is lowered in increments of one scale division until the notch signal reaches one scale division. At each increment the ratio of the two signals is determined. The ratios are plotted on the graph at the position corresponding to the larger signal. Between the limits of 20% and 80% of the screen height the ratio shall be within 10% of 2:1. Instrument settings used during inspection shall not cause variation outside the 10% limits established above. 4.2 The search unit shall be a 45-deg (in steel) angle-beam type with active transducer length and width dimensions of a minimum of 1 2 in. [12.5 mm] and a maximum of 1 in. [25 mm]. Search units of other sizes and angles may be used for additional exploration and evaluation. 5. Examination Frequency 5.1 The ultrasonic frequency selected for the examination shall be the highest frequency that permits detection of the required calibration notch, such that the amplitude 403

12 SA-577/SA-577M 1998 SECTION V SA-577/SA-577M of the indication yields a signal-to-noise ratio of at least 3:1. 6. Calibration Reflector 6.1 A calibration notch, the geometry of which has been agreed upon by the purchaser and the manufacturer, with a depth of 3% of the plate thickness, shall be used to calibrate the ultrasonic examination. The notch shall be at least 1 in. [25 mm] long. 6.2 Insert the notch or notches on the surface of the plate so that they are perpendicular to the long axis at a distance of 2 in. [50 mm] or more from the short edge of the plate. Locate the notch not less than 2 in. [50 mm] from the long edges of the plate. 6.3 When the notch cannot be inserted in the plate to be tested, it may be placed in a calibration plate of ultrasonically similar material. The calibration plate will be considered ultrasonically similar if the height of the first back reflection through it is within 25% of that through the plate to be tested at the same instrument calibration. The calibration plate thickness shall be within 1 in. [25 mm] of the thickness of plates to be tested, for plates of 2 in. [50 mm] thickness and greater and within 10% of plates whose thickness is less than 2 in. [50 mm]. 6.4 For plate thicknesses greater than 2 in. [50 mm], insert a second calibration notch as described in 6.2, on the opposite side of the plate. 7. Calibration Procedure 7.1 Plate 2 in. [50 mm] and Under in Thickness: Place the search unit on the notched surface of the plate with the sound beam directed at the broad side of the notch and position to obtain maximum amplitude from the first vee-path indication which is clearly resolved from the initial pulse. Adjust the instrument gain so that this reflection amplitude is at least 50 but not more than 75% of full screen height. Record the location and amplitude of this indication on the screen Move the search unit away from the notch until the second vee-path indication is obtained. Position the search unit for maximum amplitude and record the indication amplitude. Draw a line between the peaks from the two successive notch indications on the screen. This line is the distance amplitude curve (DAC) for this material and shall be a 100% reference line for reporting indication amplitudes. 7.2 Plate Over 2 to 6 in. [50 to 150 mm] Inclusive in Thickness: Place the search unit on the test surface aimed at the broad side of the notch on the opposite surface of the plate. Position the search unit to obtain a maximum one-half vee-path indication amplitude. Adjust the instrument gain so that this amplitude is at least 50% but not more than 80% of full screen height. Record the location and amplitude on the screen. Without adjusting the instrument settings, repeat this procedure for the vee-path indication Without adjusting the instrument settings, reposition the search unit to obtain a maximum full vee-path indication from the notch on the test surface. Record the location and amplitude on the screen Draw a line on the screen connecting the points established in and This curve shall be a DAC for reporting indication amplitudes. 7.3 Plate Over 6 in. [150 mm] in Thickness: Place the search unit on the test surface aimed at the broad side of the notch on the opposite surface of the plate. Position the search unit to obtain a maximum one-half vee-path indication amplitude. Adjust the instrument gain so that this amplitude is at least 50% but not more than 80% of full screen height. Record the location and amplitude on the screen Without adjusting the instrument settings, reposition the search unit to obtain a maximum full vee-path indication from the notch on the test surface. Record the location and amplitude on the screen Draw a line on the screen connecting the points established in and This line shall be a DAC for reporting indication amplitudes. 8. Examination Procedure 8.1 Scan one major surface of the plate on grid lines perpendicular and parallel to the major rolling direction. Grid lines shall be on 9-in. [225-mm] centers. Use a suitable couplant such as water, oil, or glycerin. Scan by placing the search unit near one edge with the ultrasonic beam directed toward the same edge and move the search unit along the grid line in a direction perpendicular to the edge to a location two plate thicknesses beyond the plate center. Repeat this scanning procedure on all grid lines from each of the four edges. 404

13 SA-577/SA-577M ARTICLE 23 ULTRASONIC STANDARDS SA-577/SA-577M 8.2 Measure grid lines from the center or one corner of the plate. 8.3 Position the search unit to obtain a maximum indication amplitude from each observed discontinuity. 8.4 For each discontinuity indication that equals or exceeds the DAC, record the location and length, and the amplitude to the nearest 25%. No indication with an amplitude less than the DAC shall be recorded. 8.5 At each recorded discontinuity location, conduct a 100% examination of the mass under a 9-in. [225-mm] square which has the recorded discontinuity position at its center. Conduct the examination in directions perpendicular and parallel to the major rolling direction. 9. Acceptance Standard 9.1 Any discontinuity indication that equals or exceeds the DAC shall be considered unacceptable unless additional exploration by the longitudinal method indicates it is laminar in nature. 10. Rehearing 10.1 The manufacturer reserves the right to discuss unacceptable ultrasonically examined plate with the purchaser with the object of possible repair of the ultrasonically indicated discontinuity before rejection of the plate. 11. Inspection 11.1 The purchaser s representative shall have access, at all times while work on the contract of the purchaser is being performed, to all parts of the manufacturer s works that concern the ultrasonic examination of the material ordered. The manufacturer shall afford the representative all reasonable facilities to satisfy him that the material is being furnished in accordance with this specification. All examinations and verifications shall be so conducted as not to interfere unnecessarily with the manufacturer s operations. 12. Marking 12.1 Plates accepted in accordance with this specification shall be identified by metal stamping or stencilling UT A 577 in one corner of the plate, at a location within 6 in. [150 mm] of the heat number. 13. Report 13.1 Unless otherwise agreed upon between the purchaser and manufacturer, the manufacturer shall report the following data: Plate identity including pin-pointed recordable indication locations, lengths, and amplitudes Examination parameters, including: couplant; search unit type, angle, frequency, and size; instrument make, model, and serial number; and calibration plate description Date of examination and name of operator. 405

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15 SA-578/SA-578M ARTICLE 23 ULTRASONIC STANDARDS SA-578/SA-578M STANDARD SPECIFICATION FOR STRAIGHT-BEAM ULTRASONIC EXAMINATION OF PLAIN AND CLAD STEEL PLATES FOR SPECIAL APPLICATIONS 1 SA-578/SA-578M (Identical with ASTM Specification A 578/A 578M-92) 1. Scope 1.1 This specification 2 covers the procedure and acceptance standards for straight-beam, pulse-echo, ultrasonic examination of rolled carbon and alloy plain and clad steel plates, 3 8 in. [10 mm] in thickness and over, for special applications. The method will detect internal discontinuities parallel to the rolled surfaces. Three levels of acceptance standards are provided. Supplementary requirements are provided for examination of clad plate and for alternative procedures. 1.2 Individuals performing examinations in accordance with this specification shall be qualified and certified in accordance with the requirements of the latest edition of ASNT SNT-TC-1A or an equivalent accepted standard. An equivalent standard is one which covers the qualification and certification of ultrasonic nondestructive examination candidates and which is acceptable to the purchaser. 1.3 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of 1 This specification is under the jurisdiction of ASTM Committee A-1 on Steel, Stainless Steel, and Related Alloys and is the direct responsibility of Subcommittee A01.11 on Steel Plates for Boilers and Pressure Vessels. Current edition approved Dec. 15, Published February Originally published as A T. Last previous edition A 578/ A 578M For ASME Boiler and Pressure Vessel Code applications, see related Specification SA-578/SA-578M in Section II of that Code. the other. Combining values from the two systems may result in nonconformance with the specification. 2. Referenced Documents 2.1 ASTM Standards: A 263 Specification for Corrosion-Resisting Chromium Steel Clad Plate, Sheet, and Strip 3 A 264 Specification for Stainless Chromium-Nickel Steel Clad Plate, Sheet, and Strip 3 A 265 Specification for Nickel and Nickel-Base Alloy Clad Steel Plate American National Standard: B 46.1 Surface Texture ASNT Standard: SNT-TC-1A 5 3. Ordering Information 3.1 The inquiry and order shall indicate the following: Acceptance level requirements (Sections 7, 8, and 9). Acceptable Level I shall apply unless otherwise agreed to by purchaser and manufacturer. 3 Annual Book of ASTM Standards, Vol Available from American National Standards Institute, 11 W. 42nd St., 13th floor, New York, NY Available from American Society for Nondestructive Testing, 1711 Arlingate Plaza, Columbus, OH

16 SA-578/SA-578M 1998 SECTION V SA-578/SA-578M Any additions to the provisions of this specification as prescribed in 5.2, 12.1, and Section Supplementary requirements, if any. 4. Apparatus 4.1 The amplitude linearity shall be checked by positioning the transducer over the depth resolution notch in the IIW or similar block so that the signal from the notch is approximately 30% of the screen height, and the signal from one of the back surfaces is approximately 60% of the screen height (two times the height of the signal from the notch). A curve is then plotted showing the deviations from the above established 2:1 ratio that occurs as the amplitude of the signal from the notch is raised in increments of one scale division until the back reflection signal reaches full scale, and then is lowered in increments of one scale division until the notch signal reaches one scale division. At each increment the ratio of the two signals is determined. The ratios are plotted on the graph at the position corresponding to the larger signal. Between the limits of 20% and 80% of the screen height, the ratio shall be within 10% of 2:1. Instrument settings used during inspection shall not cause variation outside the 10% limits established above. 4.2 The transducer shall be 1 or in. [25 or 30 mm] in diameter or 1 in. [25 mm] square. 4.3 Other search units may be used for evaluating and pinpointing indications. 5. Procedure 5.1 Perform the inspection in an area free of operations that interfere with proper performance of the test. 5.2 Unless otherwise specified, make the ultrasonic examination on either major surface of the plate. 5.3 The plate surface shall be sufficiently clean and smooth to maintain a first reflection from the opposite side of the plate at least 50% of full scale during scanning. This may involve suitable means of scale removal at the manufacturer s option. Condition local rough surfaces by grinding. Restore any specified identification which is removed when grinding to achieve proper surface smoothness. 5.4 Perform the test by one of the following methods: direct contact, immersion, or liquid column coupling. Use a suitable couplant such as water, soluble oil, or glycerin. As a result of the test by this method, the surface of plates may be expected to have a residue of oil or rust or both. 5.5 A nominal test frequency of MHz is recommended. When testing plates less than 3 4 in. [20 mm] thick a frequency of 5 MHz may be necessary. Thickness, grain size or microstructure of the material and nature of the equipment or method may require a higher or lower test frequency. Use the transducers at their rated frequency. A clean, easily interpreted trace pattern should be produced during the examination. 5.6 Scanning: Scanning shall be along continuous perpendicular grid lines on nominal 9-in. [225-mm] centers, or at the option of the manufacturer, shall be along continuous parallel paths, transverse to the major plate axis, on nominal 4-in. [100-mm] centers, or shall be along continuous parallel paths parallel to the major plate axis, on 3-in. [75-mm] or smaller centers. Measure the lines from the center or one corner of the plate with an additional path within 2 in. [50 mm] of all edges of the plate on the searching surface Conduct the general scanning with an instrument adjustment that will produce a first reflection from the opposite side of a sound area of the plate from 50% to 90% of full scale. Minor sensitivity adjustments may be made to accommodate for surface roughness When a discontinuity condition is observed during general scanning adjust the instrument to produce a first reflection from the opposite side of a sound area of the plate of 75 5% of full scale. Maintain this instrument setting during evaluation of the discontinuity condition. 6. Recording 6.1 Record all discontinuities causing complete loss of back reflection. 6.2 For plates 3 4 in. [20 mm] thick and over, record all indications with amplitudes equal to or greater than 50% of the initial back reflection and accompanied by a 50% loss of back reflection. NOTE 2 Indications occurring midway between the initial pulse and the first back reflection may cause a second reflection at the location of the first back reflection. When this condition is observed it shall be investigated additionally by use of multiple back reflections. 6.3 Where grid scanning is performed and recordable conditions as in 6.1 and 6.2 are detected along a given grid line, the entire surface area of the squares adjacent 408

17 SA-578/SA-578M ARTICLE 23 ULTRASONIC STANDARDS SA-578/SA-578M to this indication shall be scanned. Where parallel path scanning is performed and recordable conditions as in 6.1 and 6.2 are detected, the entire surface area of a 9 by 9-in. [225 by 225-mm] square centered on this indication shall be scanned. The true boundaries where these conditions exist shall be established in either method by the following techniques: Move the transducer away from the center of the discontinuity until the height of the back reflection and discontinuity indications are equal. Mark the plate at a point equivalent to the center of the transducer. Repeat the operation to establish the boundary. 7. Acceptance Standards Level I 7.1 Any area where one or more discontinuities produce a continuous total loss of back reflection accompanied by continuous indications on the same plane that cannot be encompassed within a circle whose diameter is 3 in. [75 mm] or 1 2 of the plate thickness, whichever is greater, is unacceptable. 7.2 In addition, two or more discontinuities smaller than described in 7.1 shall be unacceptable unless separated by a minimum distance equal to the greatest diameter of the larger discontinuity or unless they may be collectively encompassed by the circle described in Acceptance Standard Level II 8.1 Any area where one or more discontinuities produce a continuous total loss of back reflection accompanied by continuous indications on the same plane that cannot be encompassed within a circle whose diameter is 3 in. [75 min] or 1 2 of the plate thickness, whichever is greater, is unacceptable. 9. Acceptance Standard Level III 9.1 Any area where one or more discontinuities produce a continuous total loss of back reflection accompanied by continuous indications on the same plane that cannot be encompassed within a 1 in. [25-mm] diameter circle is unacceptable. 10. Rehearing 10.1 The manufacturer reserves the right to discuss rejectable ultrasonically tested plate with the purchaser with the object of possible repair of the ultrasonically indicated defect before rejection of the plate. 11. Inspection 11.1 The inspector representing the purchaser shall have access at all times, while work on the contract of the purchaser is being performed, to all parts of the manufacturer s works that concern the ultrasonic testing of the material ordered. The manufacturer shall afford the inspector all reasonable facilities to satisfy him that the material is being furnished in accordance with this specification. All tests and inspections shall be made at the place of manufacture prior to shipment, unless otherwise specified, and shall be conducted without interfering unnecessarily with the manufacturer s operations. 12. Marking 12.1 Plates accepted according to this specification shall be identified by stenciling (stamping) UT A on one corner for Level I, UT A for Level II, and UT A for Level III. The supplement number shall be added for each supplementary requirement ordered. 13. Report 13.1 Unless otherwise agreed to by the purchaser and the manufacturer, the manufacturer shall report the following data: All recordable indications listed in Section 6 on a sketch of the plate with sufficient data to relate the geometry and identity of the sketch to those of the plate Test parameters including: Make and model of instrument, test frequency, surface condition, transducer (type and frequency), and couplant Date of test. 409

18 SA-578/SA-578M 1998 SECTION V SUPPLEMENTARY REQUIREMENTS SA-578/SA-578M These supplementary requirements shall apply only when individually specified by the purchaser. When details of these requirements are not covered herein, they are subject to agreement between the manufacturer and the purchaser. S1. Scanning S1.1 Scanning shall be continuous over 100% of the plate surface. S2. Acceptance Standard S2.1 Any recordable condition listed in Section 6 that (1) is continuous, (2) is on the same plane (within 5% of the plate thickness), and (3) cannot be encompassed by a 3-in. [75-mm] diameter circle, is unacceptable. Two or more recordable conditions (see Section 5), that (1) are on the same plane (within 5% of plate thickness), (2) individually can be encompassed by a 3-in. [75-mm] diameter circle, (3) are separated from each other by a distance less than the greatest dimension of the smaller indication, and (4) collectively cannot be encompassed by a 3-in. [75-mm] diameter circle, are unacceptable. S2.2 An acceptance level more restrictive than Sections 7 or 8 shall be used by agreement between the manufacturer and purchaser. S3. Procedure S3.1 The manufacturer shall provide a written procedure in accordance with this specification. S4. Certification S4.1 The manufacturer shall provide a written certification of the ultrasonic test operator s qualifications. S5. Surface Finish S5.1 The surface finish of the plate shall be conditioned to a maximum 125 in. [3 m] AA (see ANSI B46.1) prior to test. S6. Examination of Integrally Bonded Clad Plate, Acceptance Level S6 S6.1 Examine the plate from the clad surface using procedures and techniques in accordance with this specification. S6.2 Inspect the backing steel to Level I, or, if specifically requested by customer, to Level II. S6.3 The cladding shall be interpreted to be unbonded when there is complete loss of back reflection accompanied by an echo indication from the plane of the interface of the clad and backing steel. S6.4 Unless otherwise specified, indications of unbond determined in accordance with S6.3 that cannot be encompassed within a 3-in. [75-mm] diameter circle shall be weld repaired subject to the requirements and limitations for the repair of defects in cladding of the appropriate material specification. S6.5 This supplementary requirement is applicable to ASTM Specifications A 263, A 264, and A 265. S7. Examination of Integrally Bonded Clad Plate, Acceptance Level S7 S7.1 The plate shall be examined from the clad surface using procedures and techniques according to this specification except 100% surface search is mandatory. S7.2 Inspect the backing steel to Level I, or, if specifically requested by customer, to Level II. S7.3 The cladding shall be interpreted to be unbonded when there is complete loss of back reflection accompanied by an echo indication from the plane of the interface of the clad and backing steel. S7.4 Unless otherwise specified, indications of unbond determined in accordance with S7.3 that cannot be encompassed within a 1-in. [25-mm] diameter circle shall be weld repaired subject to the requirements and limitations for the repair of defects in cladding of the appropriate material specification. Additionally, prior 410

19 SA-578/SA-578M ARTICLE 23 ULTRASONIC STANDARDS TABLE S8.1 CALIBRATION HOLE DIAMETER AS A FUNCTION OF PLATE THICKNESS (S8) SA-578/SA-578M Plate Thickness, in. [mm] 4 6 [ ] >6 9 [> ] >9 12 [> ] >12 20 [> ] Hole Diameter, in. [mm] 5 8 [16] 3 4 [19] 7 8 [22] [29] approval must be obtained if the weld repaired surface exceeds 1.5% of the cladding surface. S7.5 This supplementary requirement is applicable to ASTM Specifications A 263, A 264, and A 265. S8. Ultrasonic Examination Using Flat Bottom Hole Calibration (for Plates 4 in. [100 mm] Thick and Greater) S8.1 Use the following calibration and recording procedures in place of 5.6.2, 5.6.3, and Section 6. S8.2 The transducer shall be in accordance with 4.2. S8.3 Reference Reflectors T/4, T/2, and 3T/4 deep flat bottom holes shall be used to calibrate the equipment. The flat bottom hole diameter shall be in accordance with Table S8.1. The holes may be drilled in the plate to be examined if they can be located without interfering with the use of the plate, in a prolongation of the plate to be examined, or in a reference block of the same nominal composition and thermal treatment as the plate to be examined. The surface of the reference block shall be no better to the unaided eye than the plate surface to be examined. The reference block shall be of the same nominal thickness (within 75 to 125% or 1 in. [25 mm] of the examined plate, whichever is less) and shall have acoustical properties similar to the examined plate. Acoustical similarity is presumed when, without a change in instrument setting, comparison of the back reflection signals between the reference block and the examined plate shows a variation of 25% or less. S8.4 Calibration Procedure: S8.4.1 Couple and position the search unit for maximum amplitudes from the reflectors at T/4, T/2, and 3T/4. Set the instrument to produce a 75 5% of full scale indication from the reflector giving the highest amplitude. S8.4.2 Without changing the instrument setting, couple and position the search unit over each of the holes and mark on the screen the maximum amplitude from each hole and each minimum remaining back reflection. S8.4.3 Mark on the screen half the vertical distance from the sweep line to each maximum amplitude hole mark. Connect the maximum amplitude hole marks and extend the line through the thickness for the 100% DAC (distance amplitude correction curve). Similarly connect and extend the half maximum amplitude marks for the 50% DAC. S8.5 Recording: S8.5.1 Record all areas where the remaining back reflection is smaller than the highest of the minimum remaining back reflections found in S S8.5.2 Record all areas where indications exceed 50% DAC. S8.5.3 Where recordable conditions listed in S8.5.1 and S8.5.2 are detected along a given grid line, continuously scan the entire surface area of the squares adjacent to the condition and record the boundaries or extent of each recordable condition. S8.6 Scanning shall be in accordance with 5.6. S8.7 The acceptable levels of Section 7 or 8 shall apply as specified by the purchaser except that the recordable condition shall be as given in S Ultrasonic Examination of Electroslag Remelted (ESR) and Vacuum-Arc Remelted (VAR) Plates, from 1 to 16 in. [25 to 400 mm] in Thickness, Using Flat-Bottom Hole Calibration and Distance-Amplitude Corrections S9.1 The material to be examined must have a surface finish of 200 in. [5 m] as maximum for plates up to 8 in. [200 mm] thick, inclusive, and 250 in. [6 m] as maximum for plates over 8 to 16 in. [200 to 400 mm] thick. S9.2 Use the following procedures in place of 5.6.1, 5.6.2, 5.6.3, and Section 6. S9.3 The transducer shall be in accordance with 4.2. S9.4 Reference Reflectors T/4, T/2, and 3T/4 deep flat bottom holes shall be used to calibrate the 411

20 SA-578/SA-578M 1998 SECTION V TABLE S9.1 CALIBRATION HOLE DIAMETER AS A FUNCTION OF PLATE THICKNESS (S9) SA-578/SA-578M Plate Thickness, in. [mm] 1 4 [25 100] >4 8 [> ] >8 12 [> ] >12 16 [> ] Hole Diameter, in. [mm] 1 8 [3] 1 4 [6] 3 8 [10] [13] equipment. The flat bottom hole diameter shall be in accordance with Table S9.1. The flat bottoms of the holes shall be within 1 of parallel to the examination surface. The holes may be drilled in the plate to be examined if they can be located without interfering with the use of the plate, in a prolongation of the plate to be examined, or in a reference block of the same nominal composition and thermal treatment as the plate to be examined. The surface of the reference block shall be no better to the unaided eye than the plate surface to be examined. The reference block shall be of the same nominal thickness (within 75 to 125% or 1 in. [25 mm] of the examined plate, whichever is less) and shall have acoustical properties similar to the examined plate. Acoustical similarity is presumed when, without a change in instrument setting, comparison of the back reflection signals between the reference block and the examined plate shows a variation of 25% or less. S9.5 Calibration Procedure: S9.5.1 Couple and position the search unit for maximum amplitudes from the reflectors at T/4, T/2, and 3T/4. Set the instrument to produce a 75 5% of full-scale indication from the reflector giving the highest amplitude. S9.5.2 Without changing the instrument setting, couple and position the search unit over each of the holes and mark on the screen the maximum amplitude from each of the holes. S9.5.3 Mark on the screen half the vertical distances from the sweep line to each maximum amplitude hole mark. Connect the maximum amplitude hole marks and extend the line through the thickness for the 100% DAC (distance amplitude correction curve). Similarly connect and extend the half maximum amplitude marks for the 50% DAC. S9.6 Scanning Scanning shall cover 100% of one major plate surface, with the search unit being indexed between each pass such that there is at least 15% overlap of adjoining passes in order to assure adequate coverage for locating discontinuities. S9.7 Recording Record all areas where the back reflection drops below the 50% DAC. If the drop in back reflection is not accompanied by other indications on the screen, recondition the surface in the area and reexamine ultrasonically. If the back reflection is still below 50% DAC, the loss may be due to the metallurgical structure of the material being examined. The material shall be held for metallurgical review by the purchaser and manufacturer. S9.8 Acceptance Standards Any indication that exceeds the 100% DAC shall be considered unacceptable. The manufacturer may reserve the right to discuss rejectable ultrasonically examined material with the purchaser, the object being the possible repair of the ultrasonically indicated defect before rejection of the plate. 412

21 SA-609/SA-609M ARTICLE 23 ULTRASONIC STANDARDS SA-609/SA-609M STANDARD PRACTICE FOR CASTINGS, CARBON, LOW-ALLOY, AND MARTENSITIC STAINLESS STEEL, ULTRASONIC EXAMINATION THEREOF SA-609/SA-609M (Identical with ASTM Specification A 609/A 609M-86a, except Fig. 4 and its associated cross references are deleted) 1. Scope 1.1 This practice covers the standards and procedures for the pulse-echo ultrasonic examination of heat-treated carbon, low-alloy, and martensitic stainless steel castings by the longitudinal-beam technique. 1.2 This practice is to be used whenever the inquiry, contract, order, or specification states that castings are to be subjected to ultrasonic examination in accordance with Practice A 609/A 609M. 1.3 This practice contains two methods for ultrasonic inspection of carbon, low-alloy, and martensitic stainless steel castings, that is Method A and Method B. Method A is the original A 609/A 609M practice and requires calibration using a series of test blocks containing flat bottomed holes. It also provides supplementary requirements for angle beam testing. Method B requires calibration using a back wall reflection from a series of solid calibration blocks. NOTE 1 Ultrasonic examination and radiography are not directly comparable. This examination technique is intended to complement Guide E 94, in the detection of discontinuities. 1.4 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with this practice. 1.5 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Referenced Documents 2.1 ASTM Standards: A 217/A 217M Specification for Steel Castings, Martensitic Stainless and Alloy, for Pressure Containing Parts, Suitable for High-Temperature Service E 94 Guide for Radiographic Testing E 317 Practice for Evaluating Performance Characteristics of Ultrasonic Pulse-Echo Testing Systems Without the Use of Electronic Measurement Instruments 2.2 Other Document: SNT-TC-1A Recommended Practice for Non-Destructive Testing Personnel Qualification and Certification 3. Ordering Information 3.1 The inquiry and order shall specify which Method is to be used. If a method is not specified, Method A shall be used. 3.2 Method A Flat-Bottomed Hole Calibration Method: 413

22 SA-609/SA-609M 1998 SECTION V SA-609/SA-609M When this practice is to be applied to an inquiry, contract, or order, the purchaser shall furnish the following information: Quality levels for the entire casting or portions thereof, Sections of castings requiring longitudinal-beam examination, Sections of castings requiring dual element examination, Sections of castings requiring supplementary examination, using the angle-beam procedure described in Supplementary Requirement SI in order to achieve more complete examination, and Any requirements additional to the provisions of this practice. 3.3 Method B: Back-Wall Reflection Calibration Method When this method is to be applied to an inquiry, contract, or order, the purchaser shall designate the quality levels for the entire casting or applicable portions. METHOD A FLAT-BOTTOMED HOLE CALIBRATION METHOD 4. Apparatus 4.1 Electronic Apparatus: An ultrasonic, pulsed, reflection type of instrument that is capable of generating, receiving, and amplifying frequencies of at least 1 to 5 MHz The ultrasonic instrument shall provide linear presentation (within 5%) for at least 75% of the screen height (sweep line to top of screen). Linearity shall be determined in accordance with Practice E 317 or equivalent electronic means The electronic apparatus shall contain a signal attenuator or calibrated gain control that shall be accurate over its useful range to 10% of the nominal attenuation or gain ratio to allow measurement of signals beyond the linear range of the instrument. 4.2 Search Units: Longitudinal Wave, internally grounded having a 1 / 2 to 1 1 / 8 in. [13 to 28 mm] diameter or 1 in. [25 mm] square piezo-electric elements. Based on the signals-to-noise ratio of the response pattern of the casting, a frequency in the range from 1 to 5 MHz FIG. 1 ULTRASONIC STANDARD REFERENCE BLOCK shall be used. The background noise shall not exceed 25% of the distance amplitude correction curve (DAC). Transducers shall be utilized at their rated frequencies Dual-Element, 5-MHz, 1 / 2 by 1 in. [13 by 25 mm], 12 included angle search units are recommended for sections 1 in. [25 mm] and under Other frequencies and sizes of search units may be used for evaluating and pinpointing indications. 4.3 Reference Blocks: Reference blocks containing flat-bottom holes shall be used to establish test sensitivity in accordance with Reference blocks shall be made from cast steels that give an acoustic response similar to the castings being examined The design of reference blocks shall be in accordance with Fig. 1, and the basic set shall consist 414

23 SA-609/SA-609M ARTICLE 23 ULTRASONIC STANDARDS SA-609/SA-609M TABLE 1 DIMENSIONS AND IDENTIFICATION OF REFERENCE BLOCKS IN THE BASIC SET (SEE FIG. 1) Metal Overall Width or Hole Diameter Distance Length Diameter Block in 1 64 ths, in. (B), in. A (C), in. (D), min, Identification [mm] [mm] [mm] in. [mm] Number 16 [0.70] 1 [25] [45] 2 [50] [0.70] 2 [50] [70] 2 [50] [0.70] 3 [75] [95] 2 [50] [0.70] 6 [150] [170] 3 [75] [0.70] 10 [255] [275] 4 [100] [0.70] B B [125] 16-B00 B [B + 20] A Tolerance 1 8 in. [3 mm]. B Additional supplemental blocks for testing thickness greater than 10 in. [250 mm], see Machined blocks with 3 / 32 in. [24 mm] diameter flat-bottom holes at depths from the entry surface of 1 / 8 in. [3 mm], 1 / 2 in. [13 mm], or 1 / 2 t and 3 / 4 in. [19 mm], or 3 / 4 t (where t p thickness of the block) shall be used to establish the DAC for the dual-element search units (see Fig. 2) Each reference block shall be permanently identified along the side of the block indicating the material and the block identification. 4.4 Couplant A suitable couplant having good wetting characteristics shall be used between the search unit and examination surface. The same couplant shall be used for calibrations and examinations. of those blocks listed in Table 1. When section thicknesses over 15 in. [380 mm] are to be inspected, an additional block of the maximum test thickness shall be made to supplement the basic set. 5. Personnel Requirements 5.1 The manufacturer shall be responsible for assigning qualified personnel to perform ultrasonic examination in conformance with the requirements of this practice. FIG. 2 ULTRASONIC STANDARD REFERENCE BLOCK FOR DUAL-SEARCH UNIT CALIBRATION 415

24 SA-609/SA-609M 1998 SECTION V SA-609/SA-609M 5.2 Personnel performing ultrasonic examinations in accordance with this practice shall be familiar with the following: Ultrasonic terminology, Instrument calibration, Effect of transducer material, size, frequency, and mode on test results, Effect of material structure (grain size, cleanliness, etc.) on test results, Effect of test distance on test results, Effect of nonlinearity on test results, Effect of thickness and orientation of discontinuities on test results, and Effect of surface roughness on test results. 5.3 A qualification record (see Note 2) of personnel considered suitable by the manufacturer to perform examinations in accordance with this practice shall be available upon request. NOTE 2 SNT-TC-1A, Ultrasonic Testing Method, provides a recommended procedure for qualifying personnel. (Other personnel qualification requirement documents may be used when agreed upon between the purchaser and the supplier.) 6. Casting Conditions 6.1 Castings shall receive at least an austenitizing heat treatment before being ultrasonically examined. 6.2 Test surfaces of castings shall be free of material that will interfere with the ultrasonic examination. They may be as cast, blasted, ground, or machined. 6.3 The ultrasonic examination shall be conducted prior to machining that prevents an effective examination of the casting. 7. Test Conditions 7.1 To assure complete coverage of the specified casting section, each pass of the search unit shall overlap by at least 10% of the width of the transducer. 7.2 The rate of scanning shall not exceed 6 in./s [150 mm/s]. 7.3 The ultrasonic beam shall be introduced perpendicular to the examination surface. 8. Procedure 8.1 Adjust the instrument controls to position the first back reflection for the thickness to be tested at least one half of the distance across the cathode ray tube. 8.2 Using the set of reference blocks spanning the thickness of the casting being inspected, mark the flatbottom hole indication height for each of the applicable blocks on the cathode ray tube shield. Draw a curve through these marks on the screen or on suitable graph paper. The maximum signal amplitude for the test blocks used shall peak at approximately three-fourths of the screen height above the sweep by use of the attenuator. This curve shall be referred to as the 100% distance amplitude correction (DAC) curve. If the attenuation of ultrasound in the casting thickness being examined is such that the system s dynamic range is exceeded, segmented DAC curves are permitted. 8.3 The casting examination surface will normally be rougher than that of the test blocks; consequently, employ a transfer mechanism to provide approximate compensation. In order to accomplish this, first select a region of the casting that has parallel walls and a surface condition representative of the rest of the casting as a transfer point. Next, select the test block whose overall length, C (Fig. 1), most closely matches the reflection amplitude through the block length. Place the search unit on the casting at the transfer point and adjust the instrument gain until the back reflection amplitude through the casting matches that through the test block. Using this transfer technique, the examination sensitivity in the casting may be expected to be within 30% or less of that given by the test blocks. 8.4 Do not change those instrument controls and the test frequency set during calibration, except the attenuator, or calibrated gain control, during acceptance examination of a given thickness of the casting. Make a periodic calibration during the inspection by checking the amplitude of response from the 1 / 4 in. [6.4 mm] diameter flat-bottom hole in the test block utilized for the transfer. NOTE 3 The attenuator or calibrated gain control may be used to change the signal amplitude during examination to permit small amplitude signals to be more readily detected. Signal evaluation is made by returning the attenuator or calibrated gain control to its original setting. 8.5 During examination of areas of the casting having parallel walls, recheck areas showing 75% or greater loss of back reflection to determine whether loss of back reflection is due to poor contact, insufficient couplant, misoriented discontinuity, etc. If the reason 416

25 SA-609/SA-609M ARTICLE 23 ULTRASONIC STANDARDS SA-609/SA-609M for loss of back reflection is not evident, consider the area questionable and further investigate. 9. Data Reporting 9.1 The manufacturer s report of final ultrasonic examination shall contain the following data and shall be furnished to the purchaser: The total number, location, amplitude, and area when possible to delineate boundaries by monitoring the movement of the center of the search unit of all indications equal to or greater than 100% of the DAC, Questionable areas from 8.5 that, upon further investigation, are determined to be caused by discontinuities, The examination frequency, type of instrument, types of search units employed, couplant, manufacturer s identifying numbers, purchaser s order number, and data and authorized signature, and A sketch showing the physical outline of the casting, including dimensions of all areas not inspected due to geometric configuration, with the location and sizes of all indications in accordance with and Acceptance Standards 10.1 This practice is intended for application to castings with a wide variety of sizes, shapes, compositions, melting processes, foundry practices, and applications. Therefore, it is impractical to specify an ultrasonic quality level that would be universally applicable to such a diversity of products. Ultrasonic acceptance or rejection criteria for individual castings should be based on a realistic appraisal of service requirements and the quality that can normally be obtained in production of the particular type of casting Acceptance quality levels shall be established between the purchaser and the manufacturer on the basis of one or more of the following criteria: No indication equal to or greater than the DAC over an area specified for the applicable quality level of Table No reduction of back reflection of 75% or greater that has been determined to be caused by a discontinuity over an area specified for the applicable quality level of Table 2. TABLE 2 REJECTION LEVEL Area, in. 2 [cm 2 ] Ultrasonic Testing (see and Length, max, Quality Level ) in. [mm] [5] 1.5 [40] [10] 2.2 [55] 3 3 [20] 3.0 [75] 4 5 [30] 3.9 [100] 5 8 [50] 4.8 [120] 6 12 [80] 6.0 [150] 7 16 [100] 6.9 [175] Note 1 The areas in the table refer to the surface area on the casting over which a continuous indication exceeding the amplitude reference line or a continuous loss of back reflection of 75% or greater is maintained. Note 2 Areas shall be measured from the center of the search unit. Note 3 In certain castings, because of very long test distances or curvature of the test surface, the casting surface area over which a given discontinuity is detected may be considerably larger or smaller than the actual area of the discontinuity in the casting; in such cases a graphic plot that incorporates a consideration of beam spread should be used for realistic evaluation of the discontinuity Indications producing a continuous response equal to or greater than the DAC with a dimension exceeding the maximum length shown for the applicable quality level shall be unacceptable Other criteria agreed upon between the purchaser and the manufacturer Other means may be used to establish the validity of a refection based on ultrasonic inspection. NOTE 4 The areas for the ultrasonic quality levels in Table 2 of Practice A 609/A 609M refer to the surface area on the casting over which a continuous indication exceeding the DAC is maintained. NOTE 5 Areas are to be measured from dimensions of the movement of the search unit by outlining locations where the amplitude of the indication is 100% of the DAC or where the back reflection is reduced by 75%, using the center of the search unit as a reference point to establish the outline of the indication area. NOTE 6 In certain castings, because of very long metal path distances or curvature of the examination surfaces, the surface area over which a given discontinuity is detected may be considerably larger or smaller than the actual area of the discontinuity in the casting; in such cases, other criteria that incorporate a consideration of beam angles or beam spread must be used for realistic evaluation of the discontinuity. 417

26 SA-609/SA-609M 1998 SECTION V SA-609/SA-609M METHOD B BACK-WALL REFLECTION CALIBRATION METHOD 11. Apparatus 11.1 Apparatus shall be kept on a regular 6 month maintenance cycle during which, as a minimum requirement, the vertical and horizontal linearities, sensitivity, and resolution shall be established in accordance with the requirements of Practice E Search Units Ceramic element transducers not exceeding 1.25 in. [82 mm] diameter or 1 in. 2 [25 mm 2 ] shall be used Search Units Facing A soft urethane membrane or neoprene sheet, approximately in. [0.64 mm] thick may be used to improve coupling and minimize transducer wear caused by casting surface roughness Calibration/Testing The same system, including the urethane membrane, used for calibration shall be used to inspect the casting Other Inspections Other frequencies and type search units may be used for obtaining additional information and pinpointing of individual indications Couplant A suitable liquid couplant, such as clean SAE 30 motor oil or similar commercial ultrasonic couplant, shall be used to couple the search unit to the test surface. Other couplants may be used when agreed upon between the purchaser and supplier. 12. Ultrasonic Instrument 12.1 Type Pulsed ultrasonic reflection instrument capable of generating, receiving, and amplifying frequencies of 1 MHz to 5 MHz shall be used for testing Voltage Line voltage shall be suitably regulated by constant voltage equipment and metal housing must be grounded to prevent electric shock Linearity The instrument must provide a linear presentation (within 5%) of at least 1.5 in. [40 mm] sweep to peak (S/P) Calibrated Gain Control of Attenuator The instrument shall contain a calibrated gain control or signal attenuator (accurate within 10%) which will allow indications beyond the linear range of the instrument to be measured Time-Corrected Gain The instrument shall be equipped to compensate for signal decay with distance. A method should be available to equalize signal response at different depths. 13. Qualification 13.1 The requirements for pre-production qualification are as follows: Personnel The personnel qualification requirements of SNT-TC-1A are applicable. Other personnel qualification requirement documents may be used when agreed upon between the purchaser and the supplier. Records of all personnel shall be available to customers upon request Equipment The equipment shall be capable of meeting the requirements in Section Preparation 14.1 Time of Inspection The final ultrasonic acceptance inspection shall be performed after at least an austenitizing heat treatment and preferably after machining. In order to avoid time loss in production, acceptance inspection of cast surfaces may be done prior to machining. Machined surfaces shall be acceptance inspected as soon as possible after machining. Repair welds may be inspected before the postweld heat treatment Surface Finish: Machined Surfaces Machined surfaces subject to ultrasonic inspection shall have a finish that will produce an ultrasonic response equivalent to that obtained from a 250 in. [6.3 m] surface. The surface finish shall also permit adequate movement of search units along the surface Cast Surfaces All as-cast surfaces shall be equal to or better than Alloy Casting Institute Surface Indicator Scale No. 3. As-cast surfaces not acceptable to ACI-SIS-NO. 3 shall be improved Surface Condition All surfaces to be inspected shall be free of scale, machining or grinding particles, excessive paint thickness, dirt, or other foreign matter that may interfere with the inspection Position of Casting The casting shall be positioned such that the inspector has free access to the back wall for the purpose of verifying change in contour. 418

27 SA-609/SA-609M ARTICLE 23 ULTRASONIC STANDARDS SA-609/SA-609M 15. Calibration 15.1 Calibration Blocks Determine the thickness of the material to be ultrasonically inspected. For material thickness of 3 in. [75 mm] or less, use the series of 3 blocks, 1 / 2, 2, 5 in. [13, 50, 125 mm] for calibration. For a material thickness greater than 3 in., use the series of 3 blocks, 2, 5, 10 in. [50, 125, 250 mm] for calibration Calibration of Search Units For the thickness of material to be inspected, as determined in 15.1, use the following search units: For materials 3 in. [75 mm] or less in thickness, use a 2 1 / 4 MHz, 1 / 2 in. [13 mm] diameter search unit For material greater than 3 in. [75 mm] in thickness, use a 2 1 / 4 MHz, 1 in. [25 mm] diameter search unit Calibration Procedure: Set the frequency selector as required. Set the reject control in the OFF position Position the search unit on the entrant surface of the block that completely encompasses the metal thickness to be inspected and adjust the sweep control such that the back reflection signal appears approximately, but not more than three-quarters along the sweep line from the initial pulse signal Position the search unit on the entrant surface of the smallest block of the series of 3 blocks selected for calibration and adjust the gain until the back reflection signal height (amplitude) is 1.5 in. [40 mm] sweep to peak (S/P). Draw a line on the Cathode- Ray screen (CRT), parallel to the sweep line, through the peak of the 1.5 in. (S/P) amplitude Position the search unit on the entrant surface of the largest block of the series of 3 blocks selected for calibration, and adjust the distance amplitude control to provide a back reflection signal height of 1.5 in. [40 mm] (S/P) Position the search unit on the entrant surface of the intermediate calibration block of the series of 3 blocks being used for calibration and confirm that the back reflection signal height is approximately 1.5 in. [40 mm] (S/P). If it is not, obtain the best compromise between this block and the largest block of the series of 3 blocks being used for calibration Draw a line on the Cathode Ray tube screen parallel to the sweep line at 0.5 in. [13 mm] (S/P) amplitude. This will be the reference line for reporting discontinuity amplitudes For tests on machined surfaces, position the search unit on a machined surface of casting where the walls are reasonably parallel and adjust the gain of the instrument until the back reflection signal height is 1.5 in. [40 mm] (S/P). Increase the inspection sensitivity by a factor of three times (10 db gain) with the calibrated attenuator. Surfaces that do not meet the requirements of shall be inspected as specified in For inspections on cast surfaces, position the search unit on the casting to be inspected at a location where the walls are reasonably parallel and smooth (inside and outside diameter) and the surface condition is representative of the surface being inspected. Adjust the gain of the instrument until the back reflection signal height is 1.5 in. [40 mm] (S/P). Increase the inspection sensitivity by a factor of six times (16 db) by use of the calibrated control or attenuator. A significant change in surface finish requires a compensating adjustment to the gain Rejectable indications on as-cast surfaces may be reevaluated by surface preparation to 250 in. [6.3 m] finish or better, and reinspected in accordance with of this method It should be noted that some instruments are equipped with decibel calibrated gain controls, in which case the decibel required to increase the sensitivity must be added. Other instruments have decibel calibrated attenuators, in which case the required decibel must be removed. Still other instruments do not have calibrated gains or attenuators. They require external attenuators. 16. Scanning 16.1 Grid Pattern The surface of the casting shall be laid out in a 12 by 12 in. [300 by 300 mm] or any similar grid pattern for guidance in scanning. Grid numbers shall be stenciled on the casting for record purposes and for grid area identity. The stenciled grid number shall appear in the upper right hand corner of the grid. When grids are laid out on the casting surface and they encompass different quality levels, each specific area shall be evaluated in accordance with the requirements of the specific quality level designated for that area. 419

28 SA-609/SA-609M 1998 SECTION V SA-609/SA-609M 16.2 Overlap Scan over the surface allowing 10% minimum overlap of the working diameters of the search unit Inspection Requirements All surfaces specified for ultrasonic (UT) shall be completely inspected from both sides, whenever both sides are accessible. The same search unit used for calibration shall be used to inspect the casting. 17. Additional Transducer Evaluation 17.1 Additional information regarding any ultrasonic indication may be obtained through the use of other frequency, type, and size search unit. 18. Acceptance Criteria 18.1 Rejectable Conditions The locations of all indications having amplitudes greater than the 0.5 in. [13 mm] line given in , when amplitude three times (machined surfaces) or six times (cast surfaces) shall be marked on the casting surface. The boundary limits of the indication shall be determined by marking a sufficient number of marks on the casting surfaces where the ultrasonic signal equals one half the reference amplitude, 0.25 in. [6 mm]. To completely delineate the indication, draw a line around the outer boundary of the center of the number of marks to form the indication area. Draw a rectangle or other regular shape through the indication in order to form a polygon from which the area may be easily computed. It is not necessary that the ultrasonic signal exceed the amplitude reference line over the entire area. At some locations within the limits of the indication, the signal may be less than the reference line, but nevertheless still present such that it may be judged as a continuous, signal indication. Rejectable conditions are as follows and when any of the conditions listed below are found, the indications shall be removed and repair welded to the applicable process specification Linear Indications A linear indication is defined as one having a length equal to or greater than three times its width. An amplitude of 1 / 2 in. [13 mm], such as would result from tears or stringer type slag inclusion, shall be removed Non-Linear Indications: Isolated Indications Isolated indications shall not exceed the limits of the quality level designated by the customer s purchase order listed in Table 4. An isolated indication may be defined as one which the distance between it and an adjacent indication is greater than the longest dimension of the larger of the adjacent indications Clustered Indications Clustered indications shall be defined as two or more indications that are confined in a 1 in. [25 mm] cube. Clustered indications shall not exceed the limits of the quality level designated by the customer purchase order in Table 5. Where the distance between indications is less than the lowest dimension of the largest indication in the group, the cluster shall be repair welded The distance between two clusters must be greater than the lowest dimension of the largest indication in either cluster. If they are not, the cluster having the largest single indication shall be removed All indications, regardless of their surface areas as indicated by transducer movement on the casting surface and regardless of the quality level required, shall not have a through wall distance greater than 1 / 3 T, where T is the wall thickness in the area containing the indication Repair welding of cluster-type indications need only be to the extent necessary to meet the applicable quality level for that particular area. All other types of rejectable indications shall be completely removed Repair welds of castings shall meet the quality level designated for that particular area of the casting Any location that has a 75% or greater loss in back reflection and exceeds the area of the applicable quality level, and whose indication amplitudes may or may not exceed the 0.5 in. [13 mm] rejection line, shall be rejected unless the reason for the loss in back reflection can be resolved as not being caused by an indication. If gain is added and back echo is achieved without indication percent amplitude exceeding the 0.5 in. [13 mm] rejection line, the area should be accepted. 19. Records 19.1 Stenciling Each casting shall be permanently stenciled to locate inspection zones or grid pattern for ease in locating areas where rejectable indications were observed. 420

29 SA-609/SA-609M ARTICLE 23 ULTRASONIC STANDARDS TABLE 3 DIMENSIONS OF CALIBRATION BLOCKS FOR ANGLE-BEAM EXAMINATION SA-609/SA-609M Nominal Production Basic Calibration Hole Diameter Material Thickness Block Thickness (d), in Maximum Depth (t), in. [mm] (T), in. [mm] [mm 0.005] (D), in. [mm] Up to 1 [25] incl. 1 [25] or t 3 32 [2.4] [40] Over 1 to 2 [25 50] 2 [50] or t 1 8 [3.2] [40] Over 2 to 4 [50 100] 4 [100] or t 3 16 [4.8] [40] Over 4 to 6 [ ] 6 [150] or t 1 4 [6.3] [40] Over 6 to 8 [ ] 8 [200] or t 5 16 [7.9] [40] Over 8 to 10 [ ] 10 [250] or t 3 8 [9.5] [40] Over 10 [250] t See Note [40] Note 1 For each increase in thickness of 2 in. [50 mm], or fraction thereof, the hole diameter shall increase 1 16 in. [1.6 mm]. Note 2 For block sizes over 3 in. [75 mm] in thickness, T, the distance from the hole to the end of the block shall be 1 2 T, min, to prevent coincident reflections from the hole and the corner. Block fabricated with a 2-in. [50-mm] minimum dimension need not be modified if the corner and hole indications can be easily resolved. TABLE 4 ACCEPTANCE CRITERIA FOR SINGLE ISOLATED INDICATIONS Maximum Non-Linear Position of Quality Level Indication, Area, in. 2 [cm 2 ] Indication 1 0 E 2 1 [6] E 3 1 [6] O 2 [13] C 4 3 [19] E 5 3 [19] O 5 [32] C 6 5 [32] E 7 5 [32] O 7 [45] C 8 7 [45] E 9 7 [45] O 9 [58] C 10 9 [58] E 11 9 [58] O 11 [71] C Notes: (1) The area measured by movement of the center of the transducer over the casting surface. (2) O p outer wall 1 3, or inner wall 1 3. C p mid wall 1 3. E p extra wall. 421

30 SA-609/SA-609M 1998 SECTION V SA-609/SA-609M 19.2 Sketch A report showing the exact depth and surface location in relation to the stencil numbers, shall be made for each rejectable indicator found during each inspection The sketch shall also include, but not be limited to the following: Part identification numbers, Purchase order numbers, Type and size of supplemental transducers used, Name of inspector, and Date of inspection 20. Product Marking 20.1 Any rejectable areas (those indications exceeding the limits of Section 19) shall be marked on the casting as the inspection progresses. The point of marking shall be the center of the search unit. TABLE 5 ACCEPTANCE CRITERIA FOR CLUSTERED INDICATIONS Minimum Area in Which Indications Cumulative Area Must Be of Indications, Dispersed, in. 2 Quality Level in. 2 [cm 2 ] A, B [cm 2 ] C [13] 36 [232] [26] 36 [232] [39] 36 [232] [52] 36 [232] [64] 36 [232] A Regardless of wall location, that is midwall 1 3, innermost 1 3,or outermost 1 3. B Each indication that equals or exceeds the 0.5-in. [18 mm] reference line shall be traced to the position where the indication is equal to 0.25 in. [6 mm]. The area of the location, for the purpose of this evaluation, shall be considered the area that is confined within the outline established by the center of the transducer during tracing of the flaw as required. Whenever no discernible surface tracing is possible, each indication which equals or exceeds the 0.5 in. reference amplitude shall be considered 0.15 in. 2 [1 cm 2 ] (three times the area of the 1 4 diameter [6 mm] flat bottomed hole to compensate for reflectivity degradation of natural flaw) for the cumulative area estimates. C The indications within a cluster with the cumulative areas traced shall be dispersed in a minimum surface area of the casting equal to 36 in. 2 [230 cm 2 ]. If the cumulative areas traced are confined with a smaller area of distribution, the area shall be repair welded to the extent necessary to meet the applicable quality level. SUPPLEMENTARY REQUIREMENTS The following supplementary requirement shall be applied only when agreed upon between the purchaser and the supplier to achieve an effective examination of a critical casting area that cannot be effectively examined using a longitudinal beam as a result of casting design or possible discontinuity orientation. S1. Angle Beam Examination of Steel Castings S1.1 Equipment: S1.1.1 Examination Instrument Examination shall be conducted with an ultrasonic, pulsed-reflection type of system generating frequencies of at least 0.4 to 5 MHz. Properties of the electronic apparatus shall be the same as those specified in 4.1. S1.1.2 Search Units Angle-beam search units shall produce an angle beam in steel in the range from 30 to 75 inclusive, measured to the perpendicular of the entry surface of the casting being examined. It is preferred that search units shall have frequency of 0.4 to 5 MHz. S1.1.3 Calibration Blocks A set of blocks, as shown in Fig. 3, with a cast surface equivalent to SFSA-ACI grade SIS-4 5 and of a thickness comparable to the sections being examined with side-drilled holes at 1 / 4 t, 1 / 2 t, and 3 / 4 t (where t p thickness of the block) shall be used to establish an amplitude reference line (ARL). S1.2 Calibration of Equipment: S1.2.1 Construct the distance amplitude correction curve by utilizing the responses from the side-drilled 422

31 SA-609/SA-609M ARTICLE 23 ULTRASONIC STANDARDS SA-609/SA-609M FIG. 3 BASIC CALIBRATION BLOCK FOR ANGLE BEAM EXAMINATION holes in the basic calibration block for angle beam examination as shown in Fig. 3 and Table 3. S Resolve and mark the amplitudes of the 1 / 4 t and 1 / 2 t side-drilled holes from the same surface. The side-drilled hole used for the 1 / 4 t amplitude may be used to establish the 3 / 4 t amplitude from the opposite surface or a separate hole may be used. S Connect the 1 / 4 t, 1 / 2 t, and 3 / 4 t amplitudes to establish the applicable DAC. S1.2.2 The basic calibration blocks shall be made of material that is acoustically similar to the casting being examined. S1.2.3 Do not use basic calibration blocks with as cast surface equivalent to SFSA-ACI grade SIS-4 to examine castings with surface rougher than SFSA- ACI grade SIS-4. Use a machined calibration block for machined surfaces. S1.2.4 The search unit and all instrument control settings remain unchanged except the attenuator or calibrated gain control. S The attenuator or calibrated gain control may be used to change the signal amplitude during examination to permit small amplitude signals to be more readily detected. Signal evaluation is made by returning the attenuator or calibrated gain control to its original setting. S1.3 Data Reporting The supplier s report of final ultrasonic examination shall contain the following data: 423

32 SA-609/SA-609M 1998 SECTION V SA-609/SA-609M S1.3.1 The total number, location, amplitude, and area of all indications equal to or greater than 100% of the distance amplitude curve. S1.3.2 The examination frequency, type of instrument, type, and size of search units employed, couplant, transfer method, examination operator, supplier s identifying numbers, purchase order number, date, and authorized signature. S1.3.3 A sketch showing the physical outline of the casting, including dimensions of all areas not exam- ined due to geometric configuration, with the location of all indications in accordance with S S1.4 Acceptance Standards Acceptance quality levels shall be established between the purchaser and the manufacturer on the basis of one or more of the following criteria: S1.4.1 No indication equal to or greater than the DAC over an area specified for the applicable quality level of Table 2. S1.4.2 Other criteria agreed upon between the purchaser and the manufacturer. 424

33 SA-745 ARTICLE 23 ULTRASONIC STANDARDS SA-745 STANDARD PRACTICE FOR ULTRASONIC EXAMINATION OF AUSTENITIC STEEL FORGINGS SA-745 (Identical with ASTM A 745/A 745M-86 except for the deletion of 1.5) 1. Scope 1.1 This practice covers the standards and procedures for the contact, pulse-echo ultrasonic examination of austenitic steel forgings by the straight or angle beam techniques, or both. 1.2 This practice shall be used whenever the inquiry, proposal, contract, order, or specification states that austenitic steel forgings are to be subject to ultrasonic examination in accordance with ASTM A 745. Ultrasonic examination of nonmagnetic retaining ring forgings should be made to Recommended Practice A 531, not to this practice. 1.3 The values stated in either inch-pound or SI units are to be regarded as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the practice. 1.4 This practice and the applicable material specifications are expressed in both inch-pound units and SI units. However, unless the order specifies the applicable M specification designation [SI units], the material shall be furnished to inch-pound units. 2. Referenced Documents 2.1 ASTM Standards: A 531 Practice for Ultrasonic Inspection of Turbine-Generator Steel Retaining Rings E 317 Practice for Evaluating Performance Characteristics of Ultrasonic Pulse-Echo Testing Systems Without the Use of Electronic Measurement Instruments E 428 Recommended Practice for Fabrication and Control of Steel Reference Blocks Used in Ultrasonic Inspection 2.2 American Society for Nondestructive Testing Document: SNT-TC-1A Recommended Practice for Nondestructive Personnel Qualification and Certification 3. Ordering Information 3.1 When this practice is to be applied to an inquiry or purchase order, the purchaser shall furnish the following information: Quality level of examination (see Section 12) Additional requirements to this practice Applicability of supplementary requirements (see Supplementary Requirements section). 3.2 When specified, the manufacturer shall submit an examination procedure for purchaser approval that shall include, but not be limited to a sketch of the configuration as presented for ultrasonic examination showing the surfaces to be scanned, scanning directions, notch locations and sizes (if applicable), extent of coverage (if applicable), and an instruction listing calibration and inspection details and stage of manufacture. 425

34 SA SECTION V SA Apparatus 4.1 An electronic, pulsed, reflection type of instrument shall be used for this examination. The system shall have a minimum capability for operating at frequencies from 0.5 to 5.0 MHz. Either video or r-f presentation is acceptable. 4.2 The ultrasonic instrument shall provide linear presentation (within 5% of the signal height) for at least 75% of the screen height (sweep line to top of screen). This 5% linearity is descriptive of the screen presentation of amplitude. Instrument linearity shall be verified in accordance with the intent of Recommended Practice E Instruments with incremental gain control (accurate over its useful range to 10% of the nominal attenuation ratio) shall be used when possible to allow measurement of signals beyond the linear display range of the instrument. 4.4 Search Units: Search units having transducers of either quartz or other piezoelectric materials may be employed The maximum nominal active area of in. 2 [970 mm 2 ] with 1 2 -in. [13 mm] minimum to in. [30 mm] maximum dimensions or 3 4 -in. [20 mm] diameter minimum dimension shall be used for straight-beam scanning Angle-beam scanning transducers shall have a nominal active area of 1 2 to 1 in. 2 [325 to 650 mm 2 ]. The search unit used for angle-beam examination shall produce a beam angle of 30 to 70 in the material Other search units, including frequencies other than those listed in Section 8, may be used for evaluating and pinpointing indications of discontinuities. 4.5 Couplant A suitable couplant having good wetting characteristics shall be used between the transducer and the examination surface. The same couplant shall be used for calibration and examination. 4.6 Reference Blocks: All ultrasonic standard reference blocks shall be in accordance with the general guidelines of Recommended Practice E 428. However, absolute conformance to Recommended Practice E 428 is not mandatory due to the nature of the material covered by this practice The reference block grain size, as measured by the relative acoustic penetrability of the reference blocks, should be reasonably similar to the forging under examination. However, it must be recognized that large austenitic forgings vary considerably in acoustic penetrability throughout their volume due to variations in grain size and structure. Reference blocks should be chosen that reasonably approximate the average penetrability of the forging under examination. Supplementary blocks of coarser or finer grain may be used for evaluation of indications as covered in Section As an alternative method, where practicable, the appropriate size of reference hole (or holes) or notches may be placed in representative areas of the forging for calibration and examination purposes when removed by subsequent machining. When holes or notches are not removed by subsequent machining, the purchaser must approve the location of holes or notches. 5. Personnel Requirements 5.1 Personnel performing ultrasonic examination in accordance with this practice shall be qualified in accordance with Recommended Practice SNT-TC-1A. Supplement C Ultrasonic Inspection. A record of personnel considered qualified by the manufacturer to perform inspections shall be documented and available upon request. 6. Forging Conditions 6.1 Forgings shall be ultrasonically examined after heat treating. 6.2 The surfaces of the forging to be examined shall be free of extraneous material such as loose scale, paint, dirt, etc. 6.3 The surface roughness of scanning surfaces shall not exceed 250 in. [6 m] unless otherwise stated in the order or contract. 6.4 The forgings shall be machined to a simple configuration, that is, rectangular or parallel or concentric surfaces where complete volumetric coverage can be obtained. 6.5 In certain cases, such as with contour forged parts, it may be impractical to assure 100% volumetric coverage. Such forgings shall be examined to the maximum extent possible. A procedure indicating the extent of examination coverage shall be submitted for the purchaser s approval (see 3.2). 426

35 SA-745 ARTICLE 23 ULTRASONIC STANDARDS SA Procedure 7.1 Perform the ultrasonic examination after heat treatment when the forging is machined to the ultrasonic configuration but prior to drilling holes, cutting keyways, tapers, grooves, or machining sections to final contour. 7.2 To ensure complete coverage of the forging volume when scanning, index the search unit with at least 15% overlap with each pass. 7.3 The scanning rate shall not exceed 6 in. [150 mm]/s. 7.4 Scan all regions of the forging in at least two perpendicular directions to the maximum extent possible. 7.5 Scan disk and disk-type forgings using a straight beam from at least one flat face and radially from the circumference when practicable. For the purposes of this practice, a disk is a cylindrical shape where the diameter dimension exceeds the height dimension. Disktype forgings made as upset-forged pancakes shall be classified as disks for inspection purposes although at the time of inspection, the part may have a center hole, counterturned steps, or other detail configuration. 7.6 Scan cylindrical sections, ring and hollow forgings from the entire external surface (sides or circumference), using the straight-beam technique, and scan the forging in the axial direction to the extent possible. When the length divided by the diameter ratio (slenderness ratio) exceeds 6 to 1 (or axial length exceeds 24 in. [600 mm]), scan axially from both end surfaces to the extent possible. If axial penetration is not possible due to attenuation, angle-beam examination directed axially may be substituted in place of axial straight beam. Examine ring and hollow forgings having an outsidediameter to inside-diameter ratio of less than 2 to 1 and a wall thickness less than 8 in. [200 mm] by angle-beam techniques from the outside diameter or inside diameter, or both, using full node or half-node technique (see and ) as necessary to achieve either 100% volumetric coverage or the extent of coverage defined by an approved procedure (see 3.2). 8. Examination Frequency 8.1 Perform all ultrasonic examinations at the highest frequency practicable (as specified in 8.1.1, 8.1.2, or 8.1.3) that will adequately penetrate the forging thickness and resolve the applicable reference standard. Include in the ultrasonic examination report the examination frequency used. Determine the test frequency at the time of actual examination by the following guidelines: The nominal test frequency shall be 2.25 MHz. Use of this frequency will generally be restricted due to attenuation One megahertz is acceptable and will be the frequency generally applicable When necessary, due to attenuation, 0.5- MHz examination frequency may be used. The purchaser may request notification before this lower frequency is employed In the event that adequate penetration of certain regions is not possible even at 0.5 MHz, alternative nondestructive examination methods (such as radiography) may be employed to ensure the soundness of the forging by agreement between the purchaser and the manufacturer. 9. Straight-Beam Examination 9.1 Method of Calibration: Perform calibration for straight-beam examination on the flat-bottom hole size determined by the applicable quality level (see Section 12) Determine the calibration method by the test metal distance involved Thicknesses up to 6 in. [150 mm] may be examined using either the single-block or the distanceamplitude curve calibration method. (a) Single-Block Method Establish the test sensitivity on the reference standard representing the forging thickness. Drill flat-bottom holes normal to the examining surface, to midsection in material up to 1.5 in. [40 mm] in thickness and at least 0.75 in. [20 mm] in depth but no deeper than midsection in thicknesses from 1.5 to 6 in. [40 to 150 mm]. Make evaluations of indications at the estimated discontinuity depth at which they are observed using supplementary reference standards, if necessary. (b) Distance-Amplitude-Curve Correction Method Establish the test sensitivity on the reference standard whose metal travel distance represents the greater metal travel distance of the part under examination, within 1 in. [25 mm] Examine thicknesses from 6 to 24 in. [150 to 600 mm] using the distance-amplitude calibration method. Calibration to 1 2 thickness test metal 427

36 SA SECTION V SA-745 distance may be used provided examinations from two opposing surfaces are made For metal travel distances over 24 in. [600 mm], perform one of the following examinations: (a) Perform a back-reflection examination from at least one surface to QL-5 (see ) or to a purchaserapproved procedure (see 3.2). (b) On hollow-round forgings with wall thicknesses less than 8 in. [200 mm], perform an axial angle-beam scan in place of the straight-beam scan from the end surfaces. Calibration for this scan may be established on the existing axial notches required for the circumferential scan or on transverse oriented notches installed specifically for axial angle beam. 9.2 Calibration Procedure Over an indication-free area of the forging and with the proper test frequency, adjust the amplitude of the back reflection to the maximum limit of vertical linearity of the instrument. The adjusted instrument sensitivity display shall be the primary calibration reference for both the single-block and multiple-block calibration methods. If, at this gain setting, the amplitude response from the flat-bottom hole in the longest calibration block is not equal to or greater than 0.5 in. [13 mm] sweep-to-peak, adjust the instrument gain further to obtain a 0.5-in. [13 mm] sweep-to-peak minimum response. To complete the distance-amplitude correction curve, determine the remaining points defining the shape of the curve at this adjusted gain setting and mark the curve on the shield of the cathode ray tube or plot on a graph. At least three blocks shall be used with test metal distances of 3 in. [75 mm] 1 2 T, and T. However, the distance between any of the test blocks shall be in. [40 mm] minimum. If indications closer than 3 in. [75 mm] from the initial pulse must be evaluated, an additional block with in. [40 mm] test metal distance shall be used. This is the fixed reference against which all indications shall be evaluated at the maximum obtainable response at whatever depth the indications are observed. This will constitute an acceptable examination if there are no indications exceeding the acceptance limits. In large forgings, it is expected that a portion of the distance-amplitude curve will be above the vertical linearity limits of the instrument. If an indication appears in this area, readjust the instrument through the use of a calibrated gain control or through recalibration to the initial calibration level to bring the appropriate portion of the presentation on screen for evaluation of that specific area. NOTE 1 When flat surfaced reference block calibration is used for examination of forgings with surface curvature, compensation for curvature shall be made and the method for curvature correction shall be a matter of agreement between the producer and the purchaser. For diameter 80 in. [2000 mm] and over, no correction factor is required. 10. Angle-Beam Examination 10.1 Ring and hollow round forgings, as defined in 7.6, shall be angle-beam examined from their outer periphery in both circumferential directions employing the following method of calibration: Notches of 1.25 in. [30 mm] maximum surface length, with the length perpendicular to sound propagation; depth based on quality level (Section 12), either rectangular with a width not greater than twice its depth or 60 minimum to 75 maximum included angle, located in the forging so as to produce no interference with each other, shall be used as calibration standards Determine the response from the inside and outside diameter calibration notches with the search unit positioned to produce the maximum response from each notch. Adjust the sensitivity of the ultrasonic equipment so that the indication from the notch at the greatest test metal distance is at least 0.5 in. [13 mm] sweep-to-peak. Draw a straight line connecting the peaks of the responses obtained from the inside and outside diameter notches. This shall be the primary reference line. This procedure is considered full node calibration In the event that a response of at least 0.5 in. [13 mm] sweep-to-peak cannot be obtained from both the inside and outside diameter notches, calibrate from both the outer periphery (the outside diameter surface) and the inside diameter surface. Adjust the sensitivity of the ultrasonic equipment so that the indication from the notch in the opposite surface is at least 0.5 in. [13 mm] sweep-to-peak in magnitude. This procedure is considered half-node calibration. Axial angle beam may be substituted for straight beam from the end surfaces, when specified. NOTE 2 Long cylinders or cylinders with small inside diameters are difficult to examine from the inside diameter surface. Normally, neither inside diameters smaller than 18 in. [450 mm] nor long cylinders exceeding 36 in. [900 mm] in length are scanned from the inside diameter surface. 11. Evaluation of Material 11.1 Coarse-grained austenitic materials frequently display sweep noise, particularly when an examination is performed at high sensitivities. For this reason, it 428

37 SA-745 ARTICLE 23 ULTRASONIC STANDARDS SA-745 is important to critically scrutinize reportable and rejectable indications to determine whether they result from defects or grain structure. It is desirable to have several sets of calibration blocks with varying degrees of grain coarseness so that the attenuation of the defective area can be reasonably matched with a test block for a more accurate minimum defect size estimation. Due to the normal wide variation in attenuation throughout a given large austenitic forging, it is permissible to evaluate rejectable indications on the basis of alternative calibration blocks that compare more reasonably in attenuation to the defect area. It is also permissible to insert reference holes into representative areas of the forging itself, with the approval of the purchaser, to be used for calibration and evaluation of indications. Loss of back reflection results not only from internal discontinuities but also from coarse or nonuniform grain structures, variations in coupling, nonparallel reflecting surfaces and other factors that must be considered before concluding that loss of back reflection resulted from discontinuities. 12. Quality Levels for Acceptance 12.1 One of the following quality levels may be specified by the purchaser: Straight Beam: Material producing an indication response whose maximized amplitude equals or exceeds 100% of the primary reference or distance-amplitude correction curve at the estimated discontinuity depth shall be considered unacceptable. (a) QL-1 A distance-amplitude curve shall be based upon the amplitude response from No. 8 flat-bottom hole ( 8 64 in. [3 mm]). (b) QL-2 A distance-amplitude curve shall be based upon the amplitude response from No. 16 flat-bottom hole ( in. [6 mm]). (c) QL-3 A distance-amplitude curve shall be based upon the amplitude response from No. 24 flat-bottom hole ( in. [10 mm]). (d) QL-4 A distance-amplitude curve shall be based upon the amplitude response from No. 32 flat-bottom hole ( in. [13 mm]). (e) QL-5 A back reflection examination shall be performed guaranteeing freedom from complete loss of back reflection accompanied by an indication of a discontinuity. For this purpose, a back reflection of less than 5% of full screen height shall be considered complete loss of back reflection The applicable quality level will necessarily vary with test metal distance, purchasers requirements, and the type and size of forging involved. Large disks, rings, or solid forgings and complex forgings present extraordinary problems and quality level application shall be a matter of agreement between the manufacturer and the purchaser. For general guidance purposes, the following list of test metal distances versus quality level attainable is provided for general information. (a) QL-1 Generally practical for thicknesses up to 3 in. [75 mm]. (b) QL-2 Generally practical for thicknesses up to 8 in. [200 mm]. (c) QL-3 Generally practical for thicknesses up to 12 in. [300 mm]. (d) QL-4 Generally practical for thicknesses up to 24 in. [600 mm]. (e) QL-5 Frequently practical for thicknesses over 24 in. [600 mm] Angle Beam Material producing indications with amplitudes equal to or exceeding the primary reference-acceptance line (full node calibration; see ) at the estimated discontinuity depth observed shall be considered unacceptable. When examining with only one calibration notch (half node calibration: see ), material containing indications of discontinuities equal to or exceeding the notch indication amplitude shall be considered unacceptable QA-1 Angle beam reference acceptance shall be based on a notch depth of 3% of the thickness of the forging at the time of examination QA-2 Angle beam reference acceptance line shall be based on a notch depth of the lesser of 5% of the thickness of the forging at the time of inspection, or 3 4 in. [19.05 mm]. 13. Reportable Indications 13.1 A record that shows the location and orientation of all indications or groups of indications with amplitudes as defined below shall be submitted to the purchaser for information Indications accompanied by a loss of back reflection of 75% of screen height. Similar loss in back reflection without indications shall be scanned at lower frequencies; if unsuccessful, the area shall be reported as not inspected. 429

38 SA SECTION V SA Indications distinct from the normal noise level and traveling to the left or right on the cathode ray tube with movement of the transducer 1.0 in. [25 mm] or more over the surface of the forging Indications equal to or exceeding 50% of the applicable reference acceptance curve (both straight and angle beam). SUPPLEMENTARY REQUIREMENTS Supplementary requirements shall apply only when specified by the purchaser in the inquiry or order. Details of these supplementary requirements shall be agreed upon between the manufacturer and the purchaser. S1. Angle Beam Calibration Based on Final Thickness S1.1 The depth of the calibration notch (see ) shall be based upon the final ordered thickness of the forging rather than the thickness at the time of inspection. 430

39 SB-509 ARTICLE 23 ULTRASONIC STANDARDS SB-509 SPECIFICATION FOR SUPPLEMENTARY REQUIREMENTS FOR NICKEL ALLOY PLATE FOR NUCLEAR APPLICATIONS SB-509 (Identical with ASTM Specification B ) 1. Scope 1.1 This specification provides supplementary requirements for nickel alloy plate used in nuclear and other special applications. 1.2 The requirements of this specification are supplemental to the requirements of the basic material specification. NOTE The values stated in U.S. customary units are to be regarded as the standard. 2. Applicable Documents 2.1 ASME Standard: Boiler and Pressure Vessel Code (herein referenced to as the Code ), Section III. 3. Ordering Information 3.1 The order shall specify if weld repairing is permissible (see Section 6). 4. Requirements 4.1 When this specification is applied by the purchaser, the following requirements are mandatory: RZ Ultrasonic Examination (Section 5) and RO Certification (Section 7) 5. RZ Ultrasonic Examination 5.1 Apparatus: Electronic Apparatus The electronic apparatus shall be capable of producing, receiving, and displaying high-frequency electrical pulses at the required frequencies and energy levels. The equipment shall be pulse-echo type that uses a straight beam search unit Search Units Straight-beam search units shall be used. A nominal test frequency of MHz is recommended. When testing plates less than 3 4 in. (19.0 mm) thick, a frequency of 5 MHz may be necessary. Thickness, grain size, or microstructure of the material and nature of the equipment or method may require a higher or lower test frequency. Use the transducers at their rated frequency. A clean, easily interpreted trace pattern should be produced during the examination Couplant A couplant having good wetting properties shall be used. When a couplant such as oil is used, the surfaces of the plate may be expected to have a residue remaining. 5.2 Procedure: The plate surface shall be sufficiently clean and smooth to maintain a first reflection from the opposite surface of the plate at least 50% of the calibration amplitude during scanning Scanning One hundred percent of one major plate surface shall be covered by moving the search unit in parallel paths with not less than a 10% overlap. 431

40 SB SECTION V SB Calibration The instrument adjustment shall be set so that the first back reflection is 75 to 90% of full screen height when the search unit is placed on an indication-free area of the plate Evaluation When a discontinuity condition is observed during scanning, adjust the instrument to produce a first reflection from the opposite side of a sound area of the plate to 75 5% of the full scale. Maintain this instrument setting during evaluation of the discontinuity condition. 5.3 Acceptance Criteria: Any area where one or more discontinuities produce a continuous total loss of back reflection accompanied by continuous indications on the same plane that cannot be encompassed within a circle whose diameter is 3 in. (76.2 mm) or one half of the plate thickness, whichever is greater, is unacceptable In addition, two or more imperfections smaller than described in shall be unacceptable unless separated by a minimum distance equal to the greatest diameter of the larger imperfection or unless they may be collectively encompassed by the circle described in RL Weld Repair 6.1 Repair of imperfections by welding shall be permitted when mutually agreed upon between the purchaser and manufacturer. The repair welding shall be performed in accordance with Section III, Subarticle NB-2539 of the Code. 7. RO Certification 7.1 The manufacturer shall submit to the purchaser a test report certifying that the prescribed nondestructive tests were performed and the material met the requirements of this specification. The report shall also include a chart showing the location and size of any weldrepaired area. The American Society of Mechanical Engineers takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, is entirely their own responsibility. 432

41 SB-510 ARTICLE 23 ULTRASONIC STANDARDS SB-510 SPECIFICATION FOR SUPPLEMENTARY REQUIREMENTS FOR NICKEL ALLOY ROD AND BAR FOR NUCLEAR APPLICATIONS SB-510 (Identical with ASTM Specifications B ) 1. Scope 1.1 This specification provides supplementary requirements for nickel alloy rod and bar used in nuclear and other special applications. 1.2 The requirements of this specification are supplemental to the requirements of the basic material specification. NOTE 1 The values stated in U.S. customary units are to be regarded as the standard. 4. Requirements 4.1 When this specification is applied by the purchaser, the following requirements are mandatory: RM Elimination of Surface Imperfections (Section 5) RZ Ultrasonic Examination (Section 6), RX Liquid Penetrant Examination (Section 7), and RO Certification (Section 9). 2. Applicable Documents 2.1 ASTM Standards: E 114 Recommended Practice for Ultrasonic Pulse-Echo Straight-Beam Testing by the Contact Method E 165 Recommended Practice for Liquid Penetrant Inspection Method E 214 Recommended Practice for Immersed Ultrasonic Testing by the Reflection Method Using Pulsed Longitudinal Waves. 2.2 ASME Standard: Boiler and Pressure Vessel Code, (herein referenced to as the Code ), Section III. 3. Ordering Information 3.1 The order shall specify if weld repairing is permissible (see Section 8). 5. RM Elimination of Surface Imperfections 5.1 Unacceptable surface imperfections may be removed by grinding or machining provided: The remaining thickness is not reduced below that specified, The depression, after elimination of the imperfection, shall be blended uniformly into the surrounding surfaces, After elimination the area shall be reexamined by the method by which the product was originally examined to assure that the imperfection has been removed or reduced to an acceptable size, and If the elimination of the imperfection reduced the section thickness below the minimum specified, the product may be repair welded in accordance with RL. 433

42 SB SECTION V SB RX Ultrasonic Examination 6.1 Procedure Each rod or bar shall be tested in accordance with ASTM Recommended Practices E 114, or E Test Frequency The nominal frequency shall be 2.25 MHz unless variables, such as cross section, macrostructure, or grain size necessitate the use of other frequencies in order to assure adequate penetration. 6.3 Calibration The frequency and instrument adjustment shall be set so that the first back reflection is 75 to 90% of full screen height when the search unit is placed on an indication-free area of the rod or bar. 6.4 Scanning The entire volume of all rods and bars shall be examined. Scanning of rounds shall be circumferential or helical. Scanning of rectangles, squares, and hexagons shall be performed on two adjacent parallel sides. NOTE 2 Scanning is not required on the ends of the material. 6.5 Apparatus The equipment shall be of the pulseecho type using a straight-beam search unit of any type having a maximum area of 1 in. 2 (645 mm 2 ) and a minimum area of 1 2 in. 2 (322 mm 2 ). 6.6 Examination Conditions All conditions, such as ultrasonic frequency, instrument settings, type of search unit, and couplant used during calibration, shall be duplicated during the examination and evaluation. 6.7 Acceptance Criteria Material shall be unacceptable if examination results show one or more reflectors that produce indications accompanied by a complete loss of back reflection not associated with or attributable to the geometric configuration. Complete loss of back reflection is assumed when the back reflection falls below 5% of full screen height. 7. RX Liquid Penetrant Examination 7.1 Each rod or bar shall be tested by either a color contrast or fluorescent penetrant method in accordance with ASTM Recommended Practice E Evaluation of Indications: Mechanical discontinuities at the surface will be indicated by bleeding out of the penetrant; however, localized surface imperfections such as may occur from machining marks or surface conditions may produce similar indications that are not relevant to the detection of unacceptable discontinuities Any indication in excess of the acceptance standards (see 7.3) that is believed to be nonrelevant shall be regarded as unacceptable and shall be reexamined to verify whether or not actual unacceptable conditions are present. Surface conditioning may precede the reexamination. Nonrelevant indications and broad areas of pigmentation that would mask indications of defects are unacceptable Relevant indications are those that result from unacceptable mechanical discontinuities. Linear indications are those indications in which the length is more than three times the width. Rounded indications are indications that are circular or elliptical with the length less than three times the width. 7.3 Acceptance Standards: Only indications with major dimensions greater than 1 16 in. (1.6 mm) shall be considered relevant Any linear indications greater than 1 16 in. (1.6 mm) long for materials less than 5 8 in. (15.9 mm) thick, any linear indications greater than 1 8 in. (3.2 mm) long for materials from 5 8 in. (15.9 mm) thick to under 2 in. (50.8 mm) thick, and any linear indications 3 16 in. (4.8 mm) long for materials 2 in. (50.8 mm) thick and greater Rounded indications with dimensions greater than 1 8 in. (3.2 mm) for thicknesses less than 5 8 in. (15.9 mm) and greater than 3 16 in. (4.8 mm) for thicknesses 5 8 in. (15.9 mm) and greater Four or more indications in a line separated by 1 16 in. (1.6 mm) or less edge to edge Ten or more indications in any 6 in. 2 (3870 mm 2 ) of area whose major dimension is no more than 6 in. (152.4 mm) with the dimensions taken in the most unfavorable location relative to the indications being evaluated. 7.4 Defect Elimination Unacceptable conditions as defined in 7.3 may be resubmitted for inspection after defect elimination (Section 5). 8. RL Weld Repair 8.1 Repair of defects by welding shall be permitted when mutually agreed upon between the purchaser and manufacturer. The repair welding shall be performed in accordance with Section III, Subarticle NB-2539 of the Code. 434

43 SB-510 ARTICLE 23 ULTRASONIC STANDARDS 9. RO Certification 9.1 The manufacturer shall submit to the purchaser a test report certifying that the prescribed nondestructive tests were performed and the material met the requirements of this specification. The report shall also include a chart showing the location and size of any weld repaired area. SB

44

45 SB-513 ARTICLE 23 ULTRASONIC STANDARDS SB-513 SPECIFICATION FOR SUPPLEMENTARY REQUIREMENTS FOR NICKEL ALLOY SEAMLESS PIPE AND TUBE FOR NUCLEAR APPLICATIONS SB-513 (Identical with ASTM Specification B ) 1. Scope 1.1 This specification provides supplementary requirements for nickel alloy pipe and tube used in nuclear and other special applications. 1.2 The requirements of this specification are supplemental to the requirements of the basic material specification. NOTE The values stated in U.S. customary units are to be regarded as standard. 2. Applicable Documents 2.1 ASTM Standards: E 165, Recommended Practice for Liquid Penetrant Inspection Method E 213, Ultrasonic Inspection of Metal Pipe and Tubing for Longitudinal Discontinuities E 571, Recommended Practice for Electromagnetic (Eddy-Current) Examination of Nickel and Nickel Alloy Tubular Products 3. Ordering Information 3.1 The order shall specify if liquid penetrant examination is required (see Section 8). 4. Requirements 4.1 When this specification is applied by the purchaser, the requirements listed below are mandatory: RM Elimination of Surface Imperfections (Section 5). and RZ Ultrasonic Examination (Section 6) RV Eddy-Current Examination (Section 7), RO Certification (Section 9) 4.2 Repair by welding is not permitted. 5. RM Elimination of Surface Imperfections 5.1 Unacceptable surface imperfections may be removed by grinding or machining provided: The remaining thickness is not reduced below that permitted The depression, after elimination of imperfections, shall be blended uniformly into the surrounding surfaces, and After elimination of imperfections, the area shall be reexamined by the method that revealed the imperfection initially to be sure that it has been removed or reduced to an acceptable size. 6. RZ Ultrasonic Examination 6.1 Ultrasonic examination shall be performed in accordance with Method E Each pipe and tube, all sizes, shall be examined in two opposite circumferential directions. 437

46 SB SECTION V SB Sizes under in. (63.5 mm) in outside diameter shall be examined in two opposite axial directions if eddy-current examination is not meaningful. See Ultrasonic examination shall be performed in two opposite axial directions on tubular products to in. (63.5 to mm) in outside diameter. 6.2 Reference Standards The reference standard shall be of the same nominal diameter and thickness and the same nominal composition as the product which is being examined For circumferential scanning, the reference standard shall have axial notches or grooves on the inside and outside surfaces. The length shall be approximately 1 in. (25.4 mm) or less, a width not to exceed 1 16 in. (1.6 mm), and a depth not greater than the larger of in. (0.1 mm) or 5% of the nominal wall thickness For axial scanning, the reference standard shall have a transverse (circumferential) notch on the inner and outer surface. Dimensions of the transverse notch shall not exceed those of the longitudinal notch. 6.3 Functioning and Recalibration The proper functioning of the examination equipment shall be checked and the equipment shall be calibrated by use of the reference standard for a given diameter and wall thickness The frequency of checks shall be as follows: At the beginning of each production run of a given size and thickness of a given material After every 4 h or less during the production run At the end of the production run, and At any time that malfunctioning is suspected If during any check it is determined that the testing equipment is not functioning properly, all the product that has been tested since the last valid equipment calibration shall be reexamined. 6.4 Acceptance Criteria Any pipe or tube with a discontinuity that produces an indication equal to or greater than the indication from the reference standard shall be rejected. Rejected material may be resubmitted for inspection after elimination of the imperfection (Section 5). 7. RV Eddy-Current Examination 7.1 Each pipe or tube under in. (63.5 mm) in outside diameter shall be tested in accordance with Recommended practice E 571 if meaningful indications can be obtained from the reference standard notches. See Reference Standard The reference standard of a convenient length shall be prepared from a length of tube of the same nominal diameter and wall thickness, alloy, surface finish, and nominal heat treatment as the material being tested. The standard shall have one notch extending circumferentially on the outside diameter surface and one notch extending circumferentially on the inside surface. The notches shall have a length not greater than 1 in. (25 mm), a width not greater than 1 16 in. (1.6 mm), and a depth not greater than the larger of in. (0.1 mm) or 5% of the wall thickness. 7.3 Functioning and Recalibration The functioning and recalibration shall be in accordance with Acceptance Criteria Any pipe or tube with a discontinuity that produces an indication equal to or greater than the calibration standard shall be rejected. Rejected material may be resubmitted for inspection after elimination of the imperfection (Section 5) Eddy-current signals may be caused by any change in the uniformity of the pipe or tube. These changes in uniformity affect the electrical characteristic of the material and may produce an indication. When this occurs, the product shall be further examined to verify that the indication was not caused by a rejectable discontinuity. 8. RX Liquid Penetrant Examination 8.1 When specified, each pipe or tube shall be liquid penetrant tested in accordance with Recommended Practice E 165, except as modified herein Penetrant Application Keep the surfaces completely wetted for a minimum of 15 min and a maximum of 1 h and 15 min Surface Drying Remove excess penetrant and allow a drying time not to exceed 1 h prior to applying the developer Developing As soon as possible, but not later than 1 h after penetrant removal, start application of the developer. Begin inspection within 7 min after the developer has dried and complete inspection no later than 1 h and 15 min after the start. 438

47 SB-513 ARTICLE 23 ULTRASONIC STANDARDS SB Evaluation of Indications: Mechanical discontinuities at the surface will be indicated by bleeding out of the penetrant; however, localized surface imperfections such as may occur from machining marks, or surface conditions may produce similar indications that are not relevant to the detection of unacceptable discontinuities Any indication in excess of the acceptance standards (see 8.3) that is believed to be nonrelevant shall be regarded as unacceptable and shall be reexamined to verify whether or not unacceptable conditions are present. Surface conditioning may precede the reexamination. Nonrelevant indications and broad areas of pigmentation that would mask indication of defects are unacceptable Relevant indications are those that result from unacceptable mechanical discontinuities. Linear indications are those indications in which the length is more than three times the width. Rounded indications are indications that are circular or elliptical with the length less than three times the width. 8.3 Acceptance Standards: Only indications with major dimensions greater than 1 16 in. (1.6 mm) shall be considered relevant Any linear indication greater than 1 16 in. (1.6 mm) long for material less than 5 8 in. (15.9 mm) thick, greater than 1 8 in. (3.2 mm) long for material from 5 8 in. (15.9 mm) thick to under 2 in. (50.8 mm) thick and 3 16 in. (4.8 mm) long for materials 2 in. (50.8 mm) thick and greater Rounded indications with dimensions greater than 1 8 in. (3.2 mm) for thicknesses less than 5 8 in. (15.9 mm) and greater than 3 16 in. (4.8 mm) for thicknesses 5 8 in. (15.9 mm) and greater Four or more indications in a line separated by 1 16 in. (1.6 mm) or less edge to edge Ten or more indications in any 6 in. 2 (3870 mm 2 ) of area whose major dimension is no more than 6 in. (152.4 mm) with the dimensions taken in the most unfavorable location relative to the indications being evaluated. 8.4 Elimination Unacceptable conditions as defined in 8.3 may be resubmitted for inspection after elimination of the imperfection (Section 5). 9. RO Certification 9.1 The manufacturer shall submit to the purchaser a test report certifying that the prescribed nondestructive tests were performed and that the material met the requirements of this specification. 439

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49 SB-548 ARTICLE 23 ULTRASONIC STANDARDS SB-548 STANDARD METHOD FOR ULTRASONIC INSPECTION OF ALUMINUM-ALLOY PLATE FOR PRESSURE VESSELS SB-548 (Identical with ASTM Specification B ) NOTE The title was changed in May Scope 1.1 This method covers pulse-echo ultrasonic inspection of aluminum-alloy plate of thickness equal to or greater than in. (12.7 mm) for use in the fabrication of pressure vessels. The ultrasonic test is employed to detect gross internal discontinuities oriented in a direction parallel to the rolled surface such as cracks, ruptures, and laminations, and to provide assurance that only plate that is free from rejectable discontinuities is accepted for delivery. 1.2 The inspection method and acceptance criteria included in this standard shall be limited to plate of the following aluminum alloys: 1060, 1100, 3003, Alclad 3003, 3004, Alclad 3004, 5050, 5052, 5083, 5086, 5154, 5254, 5454, 5456, 5652, 6061, and Alclad This method applies only to ultrasonic tests using pulsed longitudinal waves which are transmitted and received by a search unit containing either a single crystal or a combination of electrically interconnected multiple crystals. Ultrasonic tests employing either the through-transmission or the angle-beam techniques are not included. 1.4 This method shall be used when ultrasonic inspection as prescribed herein is required by the contract, purchase order, or referenced plate specification. NOTE 1 The values stated in U.S. customary units are to be regarded as the standard. The metric equivalents of U.S. customary units may be approximate. 2. Applicable Documents 2.1 ASTM Standards: E 114 Recommended Practice for Ultrasonic Testing by the Reflection Method Using Pulsed Longitudinal Waves Induced by Direct Contact. E 214 Recommended Practice for Immersed Ultrasonic Testing by the Reflection Method Using Pulsed Longitudinal Waves, and E 317 Recommended Practice for Evaluating Performance Characteristics of Pulse-Echo Ultrasonic Testing Systems. 2.2 Other Standards: ASNT Recommended Practice for Nondestructive Testing Personnel Qualification and Certification Ultrasonic Testing Method SNT-TC-1A, Supplement C. 3. Summary of Method 3.1 The plate is inspected ultrasonically by scanning one rolled surface with a beam of pulsed longitudinal waves which is oriented in a direction perpendicular to the entry surface of the plate. The ultrasound is transmitted into the plate either by the direct contact, immersion, or liquid-column coupling method. During the scan, an indication representing the first back reflection is observed on the A-scan screen of the test instrument. 441

50 SB SECTION V SB When the test system sensitivity level is appropriately adjusted, a discontinuity is detected during the scan by noting an isolated indication associated with a loss of the first back reflection indication. The apparent size of the discontinuity is determined by measuring the total area in the scanned entry surface of the plate where the isolated indication and the loss of back reflection persist. The estimated discontinuity size and location are then compared with suitable acceptance criteria. NOTE 2 Additional information describing ultrasonic tests by the direct contact method and by the immersion method is available in Recommended Practices E 114 and E Significance 4.1 A number of factors such as the condition of the entry and back surfaces of the plate, the inclination of the ultrasonic beam with respect to the entry surface, and the performance characteristics of the test system may cause either a reduction of isolated indications or a substantial loss of back reflection and thereby could seriously impair the reliability of the test procedure outlined in this standard. 4.2 Accurate evaluations of discontinuity size also may be limited significantly by variations in beam characteristics which exist in most search units. For this reason, discontinuity size as determined by the test procedure outlined in this method is regarded as apparent or estimated in recognition of the limited quantitative value of the measurement. 4.3 Because a large number of interacting variables in a test system can adversely influence the results of an ultrasonic test, the actual quantitative effects of detected discontinuities upon the mechanical properties of the inspected plate are difficult to establish. Consequently, this ultrasonic inspection method is not applicable as an exclusive indicator of the ultimate quality and performance of pressure vessels but provides a reliable control of plate quality to avoid failure during the forming process for fabrication of vessels. 5. Apparatus 5.1 Test Instrument Any electronic device that produces pulsed longitudinal waves and displays ultrasonic reflections on an A-scan indicator when used with an appropriate search unit is satisfactory. The instrument shall provide stable, linear amplification of received pulses at a selected test frequency and shall be free from significant interface signal interference at the required sensitivity level. 5.2 Search Unit The search unit recommended for this standard is the flat nonfocusing type, and contains a piezoelectric crystal which generates and receives longitudinal waves at the rated frequency when connected to the test instrument through a suitable coaxial cable. A dual-crystal search unit containing both a transmitting and a receiving crystal in one container may be used provided the test instrument will accommodate two-crystal operation and the resulting pulse-echo test is equivalent to that obtained with a search unit containing a single-crystal The total effective area of the crystal or combination of crystals in the search unit used for initial scanning shall not be less than 0.4 in 2 (2.6 cm 2 ) nor greater than 1.5 in. 2 (9.7 cm 2 ) The effective diameter of the round search unit used to evaluate discontinuity size shall not exceed 0.75 in. (19 mm). NOTE 3 For control purposes, the performance characteristics of the test instrument and search unit may be established in accordance with procedures outlined in Recommended Practice E Tank For tests by the immersion method, any container is satisfactory that will facilitate the accurate, stable positioning of both the search unit and the plate to be inspected. 5.4 Scanning Apparatus During the inspection procedure, the search unit is supported by any one of the following devices. The scanning apparatus shall permit measurement of both the scan distance and the index distance within 0.1 in. ( 2 mm) Manipulator and Bridge When a manipulator is used in tests by the immersion method, the manipulator shall adequately support a search tube containing a search unit and shall provide fine adjustment of angle within 1 deg in two vertical planes that are perpendicular to each other. The bridge shall be of sufficient strength to provide rigid support for the manipulator and shall allow smooth, accurate positioning of the search unit. Special search unit supporting fixtures may be used provided they meet the requirements prescribed for a manipulator and bridge Liquid Coupling Nozzle For tests by the liquid-column coupling method, the nozzle is usually positioned manually and shall be capable of containing the couplant while rigidly supporting the search unit with its active surface immersed in the couplant. The couplant distance shall be maintained so that the second 442

51 SB-548 ARTICLE 23 ULTRASONIC STANDARDS SB-548 couplant reflection is to the right of the first back reflection on the instrument cathode ray tube (CRT). The couplant path shall not vary more than 1 4 in. (6.4 mm) during calibration, initial scanning, and discontinuity evaluation. The recommended minimum inside dimension of the nozzle is 1.0 in. (25 mm) greater than the maximum dimension of the crystal surface in the search unit. Provisions also should be included for adjustment of search unit inclination within 1 deg in two vertical planes that are perpendicular to each other. NOTE 4 Nozzles containing either sealed or unsealed openings may be used for inspecting plate provided the test results obtained with either device are equivalent to those obtained by the immersion method Contact Scanning Unit During tests by the contact method, the search unit usually is supported and positioned manually on the entry surface of the inspected plate. However, special fixtures for contact scanning may be employed provided their use ensures conformance to the requirements in this specification. 5.5 Couplant Clean, deaerated water at room temperature is the recommended couplant for tests either by the immersion method or by the liquid-column coupling technique. Inhibitors or wetting agents or both may be used. For tests by the contact method, the recommended couplant is clean, light-grade oil. NOTE 5 Other coupling liquids may be employed for inspecting plate provided their use does not adversely affect test results. 6. Personnel Requirements 6.1 The testing operator performing the ultrasonic examination prescribed in this standard shall be qualified and certified to Level I Ultrasonic Testing in accordance with the ASNT Recommended Practice SNT-TC- 1A, Supplement C. 6.2 The required documentation supporting qualification and certification of ultrasonic testing operators shall be established by the certifying agency and shall be available upon request by the purchaser. 7. Condition of Plate 7.1 The entry and back surfaces of the inspected plate shall be sufficiently clean, smooth, and flat to maintain a first back reflection amplitude greater than 50 percent of the initial standardization amplitude while scanning an area in the plate that does not contain significant isolated ultrasonic discontinuities. 7.2 The inspected plate shall be at room temperature during the test. 8. Procedure 8.1 Preferred Method The ultrasonic test may be performed by either the liquid column coupling, the direct contact, or the immersion methods. However, the immersion method is preferred Maintain the couplant distance so that the second couplant reflection is to the right of the first back reflection on the instrument cathode ray tube (CRT). The couplant path shall not vary more than 1 4 in. (6.4 mm) during calibration, initial scanning, and discontinuity evaluation. 8.2 Test Frequency When using any of the three methods listed in 8.1, the recommended test frequency is 5.0 MHz. Other test frequencies between 2.0 MHz and 10.0 MHz may be employed when necessary to minimize possible adverse effects of plate thickness, microstructure, and test system characteristics upon test results and thereby maintain a clean, easily interpreted A-scan screen pattern throughout the inspection. 8.3 Sensitivity Standardization Standardize the sensitivity level of the test system operating at the selected frequency by adjusting the instrument gain control to obtain a first back reflection amplitude of 75 5 percent of the vertical limit exhibited by the A-scan indicator when the search unit is positioned over an area free from significant discontinuities in the plate to be inspected. During tests by either the immersion method or the liquid column coupling method, adjust the angular alignment of the search unit to obtain a maximum number of back reflections before the final sensitivity level is established. 8.4 Scanning With no further adjustments of the instrument gain controls, locate the search unit over one corner of the plate to be inspected so that the edge of the crystal in the search unit is about 1 in. (25 mm) from either edge of the plate Subsequent to checking the angular alignment of the search unit with respect to the rolled entry surface to ensure a maximum first back reflection, proceed to scan the plate continuously by moving the search unit at a constant scanning rate not exceeding 12 in. (305 mm)/s from the initial starting position to the opposite edge in a direction perpendicular to the predominant rolling direction of the plate. 443

52 SB SECTION V SB During the scan, note the occurrence of isolated discontinuity indications and monitor the amplitude of the first back reflection by continuously observing the A-scan indicator screen. NOTE 6 Auxiliary monitoring devices may be employed in the test system to enhance detection reliability during the scan. 8.5 Scan Index When the initial scan is completed, move the search unit over a predetermined scan index distance in a direction parallel to the predominant rolling direction of the plate and proceed with a second scan along a line parallel to the initial scanning direction while observing the test pattern on the A-scan indicator screen. Calculate the scan index distance as follows: Scan index distance (in.). Scan index distance (mm). S i p D s S i p D s where: D s p actual crystal diameter Continue the inspection by constantly observing the test pattern on the A-scan indicator while successively scanning the plate at a constant scanning rate in a direction perpendicular to the predominant rolling direction of the plate and indexing the search unit through the index distance calculated in During the inspection procedure, check the test system sensitivity standardization periodically by noting the amplitude of the first back reflection when the search unit is repositioned over the reference area of the plate and by adjusting the instrument gain control as required to maintain the sensitivity standardization specified previously in Scanning Rate When the screen pattern on the A-scan indicator is monitored visually by the test operator during the inspection, the scanning rate shall not be greater than 12 in./s. NOTE 7 Scanning rates greater than 12 in./s may be employed if auxiliary monitoring apparatus is used to maintain adequate detection reliability. 8.7 Detection of Discontinuities When an isolated ultrasonic indication of amplitude greater than 30 percent of the A-scan vertical limit is encountered or when the first back reflection indication decreases to an amplitude less than 5 percent of the vertical limit at any time during the inspection procedure, stop the scan and angulate the search unit to obtain a maximum isolated indication and to determine that the loss of back reflection is not caused by misalignment of the search until with respect to the plate To ensure that the loss of back reflection is not caused by surface interference, check the condition of both the entry and back surfaces of the plate at the location where a substantial (95 percent or greater) loss of back reflection occurs Either a maximized isolated ultrasonic indication exhibiting an amplitude greater than 50 percent of the amplitude of the initial first back reflection used for standardization, or a substantial loss of the first back reflection indication not attributable to either search unit misalignment or surface interference, is an indication of an internal discontinuity. NOTE 8 Isolated indications occurring midway between the entry surface indication and the first back reflection may cause a second indication at the location of the first back reflection on the A-scan screen. When this condition is verified by checking the multiple back reflection pattern, a complete loss of the first back reflection can be assumed. 8.8 Estimation of Discontinuity Size Note the location of the search unit where the scan was stopped when either an isolated indication or a loss of back reflection was observed Using a search unit containing a crystal of effective diameter no greater than 0.75 in. (19 mm), make an evaluation scan of an entire 6-in. (152-mm) square area which is centered around the point on the plate entry surface where the scan was discontinued. The recommended index distance for this evaluation is as follows: S i (in. or mm) p 0.7 D s, where D s is the actual diameter of the search unit crystal To determine the apparent size of the discontinuity, mark each location corresponding to the center of the search unit on the plate entry surface where a 95 5 percent loss of first back reflection is observed or where the isolated indication exhibits an amplitude equal to 50 5 percent of the amplitude of the initial first back reflection established during the standardization procedure outlined in Continue to mark the location of the search unit at each point where either or both of the discontinuity conditions specified in paragraph are observed. The entire discontinuity shall be outlined even if it extends beyond the original 6-in. (152-mm) square evaluation scan area The estimated discontinuity size is the area defined by the boundary consisting of successive marks as established by this procedure. 444

53 SB-548 ARTICLE 23 ULTRASONIC STANDARDS SB-548 FIG. 1 STAMP FOR IDENTIFYING ACCEPTABLE PLATE NOTE 9 Automatic recording devices may be used to establish the estimated size of a discontinuity provided the recorded results are equivalent to those obtained by the procedure presented in When the estimated size of a detected discontinuity is determined, return the search unit to the original stopping position and continue the initial scan to complete the inspection. 9. Acceptance Standards 9.1 Upon completing the inspection procedure, measure the longest dimension of each marked area representing a detected discontinuity. Also, when an engineering drawing showing the part to be fabricated from the plate is supplied, compare the locations of the discontinuities with the dimensions on the drawing. 9.2 If the longest dimension of the marked area representing a discontinuity causing a complete loss of back reflection (95 percent or greater) exceeds 1.0 in. (25 mm), the discontinuity is considered to be significant and the plate shall be subject to rejection. 9.3 If the length of the marked area representing a discontinuity causing an isolated ultrasonic indication without a complete loss of back reflection (95 percent or greater) exceeds 3.0 in. (76 mm), the discontinuity is considered to be significant and the plate shall be subject to rejection. 9.4 If each of two marked areas representing two adjacent discontinuities causing isolated ultrasonic indications without a complete loss of back reflection (95 percent or greater) is longer than 1.0 in., and if they are located within 3.0 in. of each other, the proximity between the two discontinuities is considered to be significant, and the plate shall be subject to rejection. NOTE 10 A template containing a 1.0-in. diameter hole and a 3.0- in. diameter hole is a convenient device for rapidly establishing the significance of discontinuities. If the discontinuities described in 9.2 and 9.3 cannot be totally enclosed within either the 1.0-in. diameter circle or the 3.0-in. diameter circle, respectively, then the plate containing such discontinuities shall be subject to rejection. Similarly, if any portions of two adjacent discontinuities greater than 1.0 in. in length as in accordance with 9.4 appear within the 3.0-in. diameter circle, the plate shall be subject to rejection. 9.5 A plate containing significant discontinuities of rejectable size shall be acceptable if it is established by the purchaser that the discontinuities will be removed from the plate by machining during the subsequent fabrication process. 9.6 Upon specific consent of the purchaser, a plate with significant discontinuities may be accepted if repaired by welding. 10. Report 10.1 When required by the purchaser, a report shall be prepared and shall include the date of test and a list of parameters including the type (model number) of instrument and search unit, the test method, frequency, and the couplant employed for the inspection Preparation of a drawing showing the location of all significant discontinuities in the inspected plate is recommended when the ultimate rejection or acceptance of the plate is to be determined by negotiation between the manufacturer and the purchaser The identification of an acceptable plate is desirable and is recommended. For this purpose, a suitable stamp should be employed to indicate conformance to this ultrasonic standard. The recommended stamp for identifying acceptable plate is shown in Fig

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55 SE-114 ARTICLE 23 ULTRASONIC STANDARDS SE-114 RECOMMENDED PRACTICE FOR ULTRASONIC PULSE-ECHO STRAIGHT-BEAM TESTING BY THE CONTACT METHOD SE-114 (Identical with ASTM Specification E ) 1. Scope 1.1 This practice covers ultrasonic examination of materials by the pulse-echo method using straight-beam longitudinal waves introduced by direct contact of the search unit with the material being examined. 1.2 This practice shall be applicable to development of an examination procedure agreed upon by the users of the document. 1.3 The values stated in inch-pound units are to be regarded as the standard. 1.4 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of whomever uses this standard to consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Applicable Document 2.1 ASTM Standard: E 317 Practice for Evaluating Performance Characteristics of Ultrasonic Pulse-Echo Testing Systems Without the Use of Electronic Measurement Instruments 3. Significance and Use 3.1 A series of electrical pulses is applied to a piezoelectric element (transducer) which converts these pulses to mechanical energy in the form of pulsed waves at a nominal frequency. This transducer is mounted in a holder so it can transmit the waves into the material through a suitable wear surface and couplant. The assembly of transducer, holder, wearface, and electrical connector comprise the search unit. 3.2 Pulsed energy is transmitted into materials, travels in a direction normal to the contacted surface, and is reflected back to the search unit by discontinuity or boundary interfaces which are parallel or near parallel to the contacted surface. These echoes return to the search unit, where they are converted from mechanical to electrical energy and are amplified by a receiver. The amplified echoes (signals) are usually presented in an A-scan display on a cathode ray tube (CRT), such that the entire round trip of pulsed energy within the resolution of the system may be indicated along the horizontal base line of a CRT by vertical deflections corresponding to echo amplitudes from each interface, including those from intervening discontinuities. By adjustment of the sweep (range) controls, this display can be expanded or contracted to obtain a designated relation between the CRT signals and the material reflectors from which the signal originates. Thus a scaled distance to a discontinuity and its displayed signal becomes a true relationship. By comparison of the displayed discontinuity signal amplitudes to those from a reference standard, both location and estimated discontinuity size may be determined. Discontinuities having dimensions exceeding the size of the sound beam can also be estimated by determining the amount of movement of a search unit over the examination surface where a discontinuity signal is maintained. 447

56 SE SECTION V SE-114 NOTE 1 When determining the sizes of discontinuities by either of these two practices, only the area of the discontinuity which reflects energy to the search unit is determined. 3.3 Types of information that may be obtained from the pulsed-echo straight-beam practice are as follows: Apparent discontinuity size (Note 2) by comparison of the signal amplitudes from the test piece to the amplitudes obtained from a reference standard Depth location of discontinuities by calibrating the horizontal scale of the CRT screen Material properties as indicated by the relative sound attenuation or velocity changes of compared items The extent of bond and unbond (or fusion and lack of fusion) between two ultrasonic conducting materials if geometry and materials permit. NOTE 2 The term apparent is emphasized since true size depends on orientation, composition, and geometry of the discontinuity and equipment limitations. 4. Apparatus 4.1 Complete ultrasonic apparatus shall include the following: Instrumentation The ultrasonic instrument shall be capable of generating, receiving, and amplifying high-frequency electrical pulses at such frequencies and energy levels required to perform a meaningful examination and to provide a suitable readout Search Units The ultrasonic search units shall be capable of transmitting and receiving ultrasound in the material at the required frequencies and energy levels necessary for discontinuity detection. Typical search unit sizes usually range from 1 8 in. (3.2 mm) in diameter to in. (28.6 mm) in diameter with both smaller and larger sizes available for specific applications. Search units may be fitted with special shoes for appropriate applications. Special search units encompassing both a transmitter and a receiver as separate piezoelectric elements can be utilized to provide some degree of improved resolution near the examination surface Couplant A couplant, usually a liquid or semi-liquid, is required between the face of the search unit and the examination surface to permit or improve the transmittance of ultrasound from the search unit into the material under test. Typical couplants include water, cellulose gel, oil, and grease. Corrosion inhibitors or wetting agents or both may be used. Couplants must be selected that are not detrimental to the product or the process. The couplant used in calibration should be used for the examination. During the performance of a contact ultrasonic examination, the couplant layer between search unit and examination material must be maintained such that the contact area is held constant while maintaining adequate couplant thickness. Lack of couplant reducing the effective contact area or excess couplant thickness will reduce the amount of energy transferred between the search unit and the examination piece. These couplant variations in turn result in examination sensitivity variations The couplant should be selected so that its viscosity is appropriate for the surface finish of the material to be examined. The examination of rough surfaces generally requires a high viscosity couplant. The temperature of the material s surface can change the couplant s viscosity. As an example, in the case of oil and greases, see Table At elevated temperatures as conditions warrant, heat resistant coupling materials such as silicone oils, gels, or greases should be used. Further, intermittent contact of the search unit with the surface or auxiliary cooling of the search unit may be necessary to avoid temperature changes that affect the ultrasonic wave characteristics of the search unit. At higher temperatures, certain couplants based on inorganic salts or thermoplastic organic materials, high temperature delay materials, and search units that are not damaged by high temperatures may be required Where constant coupling over large areas is needed, as in automated examination, or where severe changes in surface roughness are found, other couplants such as liquid gap coupling will usually provide a better examination. In this case, the search unit does not contact the examination surface but is separated by a distance of about 0.2 in. (0.5 mm) filled with couplant. Liquid flowing through the search unit fills the gap. The flowing liquid provides the coupling path and has the additional advantage of cooling the search unit if the examination surface is hot An alternative means of direct contact coupling is provided by the wheel search unit. The search unit is mounted at the required angle to a stationary axle about which rotates a liquid-filled flexible tire. A minimum amount of couplant provides ultrasonic transmission into the examination surface since the elastic tire material is in rolling contact and conforms closely to the surface. 448

57 SE-114 ARTICLE 23 ULTRASONIC STANDARDS SE Reference Standards The production item itself may be an adequate standard using the height of the back wall echo for reference. For more quantitative information, machined artificial reflectors (discontinuities) or charts representing distance-amplitude relationships of known reflector sizes for a particular search unit and material may be used for calibration. These artificial reflectors may be in the form of flat-bottom holes, side-drilled holes, or slots. The surface finish of the reference standard should be similar to the surface finish of the production item (or corrected; see 5.3). The reference standard material and the production material should be acoustically similar (in velocity and attenuation). The reference standard selected shall be used by the examiner as the basis for signal comparisons. 5. Calibration of Equipment 5.1 If quantitative information is to be obtained, vertical or horizontal linearity or both should be checked in accordance with Practice E 317 or another procedure approved by the users of the document. An acceptable linearity performance may be agreed upon by the users of the document. 5.2 Prior to examination, calibrate the system in accordance with the product specification. 5.3 Where the surface finishes of the reference standard and the production item do not match, or where there is an acoustic difference between the standard and the production item, an attenuation correction should be made to compensate for the difference. The attenuation correction is accomplished by noting the difference between signals received from the same reference reflector (that is, back reflection) in the basic calibration (reference) block and in the production material, and correcting for this difference. 5.4 It should be recognized that near-field effects may cause sensitivity inconsistencies when searching for inhomogeneities smaller than the effective beam diameter. Suitable delay line search units or other means such as inspecting from both sides of the item may be considered where the application warrants fine scrutiny. When performing examinations in the far-field, it is recommended that compensation be made for the acoustic attenuation of the test material with respect to a certain reference standard. This compensation may be accomplished with multiple depth reference reflectors, electronically, with attenuation curves drawn on the face of the CRT, or with charts for distance-amplitude relationships of known reflectors. For optimum examina- tion performance, compensations should be made for both near and far-field effects. 5.5 Unless otherwise specified, the initial pulse and at least one back reflection shall appear on the screen of the CRT while examining for discontinuities in materials having parallel surfaces. The total number of back reflections depends upon equipment, geometry and material type, information desired, or operator preference. Reduction of the back reflection during scanning is indicative of increased attenuation or sound scattering discontinuities provided that front and back surface roughness and parallelism of the production piece are approximately the same as that of the standard. For non-parallel surfaces, the time trace of the CRT screen shall be calibrated by reference standards to include the maximum thickness being examined on the production item. 5.6 For bond/unbond (fusion/lack of fusion) examinations, a reference standard should be used similar to the production item being examined containing areas representing both bonded (fused) and unbonded (lack of fusion) conditions, if geometry and material permit. 5.7 Calibration with respect to reference standards should be periodically checked to ensure that the ultrasonic system calibration is not changing. As a minimum, the calibration shall be checked each time there is a change of operators, when search units are changed, when new batteries are installed, when equipment operating from one power source is changed to another power source, or when improper operation is suspected. 6. Procedure 6.1 When ultrasonic examinations are performed for the detection or sizing of discontinuities, or both, reflectors not perpendicular to the ultrasonic beam may be detected at reduced amplitudes, with a distorted envelope depending upon the reflector area, whether it is curved or planar, whether it is smooth or rough, perhaps with reflecting facets. Reflector characteristics may also cause rapid shifts in apparent depth as the search unit approaches or moves away from the low amplitude indication. Another effect of these reflectors is the loss of back reflection which occurs when the discontinuity lies directly between the search unit and the back surface. Reflectors detectable due to any of the foregoing phenomena cannot be sized solely on signal amplitude but require special corrections for search unit and flaw characteristics. 449

58 SE SECTION V SE Examination Surface Surfaces shall be uniform and free of loose scale and paint, discontinuities such as pits or gouges, weld splatter, dirt, or other foreign matter which affect examination results. Tightly adhering paint, scale, or coatings do not necessarily need to be removed for examining if they present uniform attenuation characteristics. The examination surface must be adequate to permit ultrasonic examination at the sensitivity specified. If needed, surfaces may be ground, sanded, wire brushed, scraped, or otherwise prepared for examining purposes. Curved surfaces, either concave or convex, may be examined; however, the calibration system should compensate for the effective change in search unit transmitting area between the reference standard and production item. If practical, the reference standard should have the same geometry as the item being examined. 6.3 Search Unit Select a suitable search unit size and frequency after consideration of the acoustic characteristics of material to be examined, the geometry of the production item, and the minimum size and type of discontinuity to be detected. The higher the frequency selected, the higher the resolving capability accompanied with a decrease in penetrating power; conversely, the lower the frequency used, the greater the penetrating power with decreasing resolving capability. Factors limiting the use of higher frequencies are the equipment and the material properties. The limiting use of lower frequencies is the loss in sensitivity level for the examination. Various types of straight-beam search units are available offering advantages for specific applications. The above statements should be considered when choosing the search unit size, type, and frequency. When delay materials are used in the search unit, the calibration and examination surface temperatures should be within 25 F (14 C) to avoid large attenuation and velocity differences. NOTE 3 The largest diameter and highest frequency search units yielding desired results should be used for maximum resolution and good beam directivity. 6.4 Scanning Scanning may be either continuous or intermittent, depending upon the geometry, application, and requirements of the part being examined. For continuous scanning, the search unit indexing must be adequate to provide 100% coverage, at uniform examination sensitivity, of the area being examined. Adjust scanning speed or instrument repetition rate or both to permit detection of the smallest discontinuities referenced in the specification and to allow the recording or signaling device to function Manual Scanning Hold the search unit in the hand and move over the surface of the production piece Automated Scanning The search unit is held by a suitable fixed device and either the production piece moves or is held stationary while the search unit moves mechanically along some predetermined path. For automated scanning, monitor coupling between the search unit and part either electronically or visually to ensure proper examination sensitivity. 6.5 During the evaluation of indications, maintain the same relative sensitivities between the reference standard and the production item. Make an evaluation of ultrasonic indications after response reflections from discontinuities are maximized by search unit manipulation. Map discontinuity extremities larger than the sound beam. A recommended method for mapping, on the surface of the production piece, the apparent size (that is, the reflecting surface seen by the search unit) of discontinuities larger than the search unit is by the half-amplitude method. Position the search unit over the discontinuity for maximum signal response and move in one direction until the signal drops rapidly to the base line on the CRT. Then return the search unit to the position where the signal was half the amplitude that it had at the point where the indication began to drop rapidly to the base line. At this point the center of the search unit should approximately coincide with the edge of the discontinuity. Repeat this procedure for other directions as necessary to outline the discontinuity on the surface. Search units of other frequencies and sizes may be used for mapping to obtain greater accuracy. Special consideration should be given to discontinuities when the signal amplitude drops to half the maximum amplitude or less, and remains at the lower level over extended distances (for example, more than half the search unit diameter). NOTE 4 For rounded surfaces, geometry must be considered when using this method. 7. Examination Data Record 7.1 The following data should be recorded as a minimum for future reference at the time of each examination: Part number identification, Operator s name and level (if certified), Instrument description, make, model, and serial number, 450

59 SE-114 ARTICLE 23 ULTRASONIC STANDARDS SE Setup Couplant, cable type and length, manual/automatic scanning, Search unit description Type, size, frequency, special shoes, Reference standards (and calibration data required to duplicate the examination) Indication information as specified by the applicable specification, or results of the examination (number, classification, and location of discontinuities). For bond/unbond (fusion/lack of fusion) examinations the extent of unbond (lack of fusion) or bond (fusion) should be reported. 8. Interpretation of Results 8.1 Advance agreement should be reached by users of this document as applicable regarding the interpretation of the results of the examinations and how they shall be recorded. All discontinuities having signals that exceed the rejection level as defined by the material specification, drawing, or purchase order shall be re- jected unless it is determined from the machine part drawing that the rejectable discontinuities will not remain in the finished part. 9. Report 9.1 The report shall include the information agreed upon by users of this document. TABLE 1 SUGGESTED VISCOSITIES OIL COUPLANTS Approximate Surface Roughness Average (Ra), in. ( m) Equivalent Couplant Viscosity, Weight Motor Oil ( ) SAE ( ) SAE ( ) SAE ( ) SAE 40 Over 700 (18 ) cup grease Note The table is a guide only and is not meant to exclude the use of a particular couplant that is found to work satisfactorily on a particular surface. 451

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61 SE-213 ARTICLE 23 ULTRASONIC STANDARDS SE-213 STANDARD PRACTICE FOR ULTRASONIC INSPECTION OF METAL PIPE AND TUBING SE-213 (Identical with ASTM Specification E ) 1. Scope 1.1 This practice covers a procedure for detecting discontinuities in metal pipe and tubing using pulsereflection ultrasonic contact or immersion oblique angle techniques. Artificial discontinuities consisting of longitudinal reference notches are employed as the primary means of calibrating the ultrasonic system. If transverse as well as longitudinal inspection is desired, a procedure for employing transverse notches is provided. 1.2 This practice is intended for use with tubular products having outside diameters from approximately 1 2 to 6 in. (12.7 to 152 mm). These procedures have been used successfully for smaller and larger sizes, however, and may be specified upon contractual agreement between the purchaser and the supplier. 2. Applicable Documents 2.1 ASTM Standards: E 500 Definitions of Terms Relating to Ultrasonic Testing. 4. Ordering Information 4.1 The following are items that require agreement between the purchaser and the supplier, and should be specified in the purchase specification or elsewhere: Size and type of tubing to be examined, Extent of examination, that is, scanning in one or both circumferential directions, scanning in one or both axial directions, weld zone only if welded, pitch of feed helix during scanning, etc., Time of examination, that is, the point(s) in the manufacturing process at which the material will be examined, Surface condition, Maximum time interval between equipment calibration cheeks, if different from that described in 10.2, Type, dimensions, location, method of manufacture, and number of artificial discontinuities to be placed on the calibration standard, Method(s) for measuring dimensions of artificial discontinuities and tolerance limits if different than specified in Section 8, Criteria for reportable and rejectable indications (that is, acceptance criteria), 3. Significance and Use 3.1 The purpose of this practice is to outline a procedure for detecting and locating significant discontinuities such as pits, voids, inclusions, cracks, splits, etc., by the ultrasonic pulse-reflection method Limitations on conditioning (reworking) processes used to remove surface discontinuities, if applicable, Requirements for permanent records of the response from each tube, if applicable, 453

62 SE SECTION V SE Contents of testing report, and Operator qualifications and certification, if required. 5. Surface Condition 5.1 All surfaces shall be clean and free of scale, dirt, grease, paint, or other foreign material that could interfere with interpretation of test results. The methods used for cleaning and preparing the surfaces for ultrasonic inspection shall not be detrimental to the base metal or the surface finish. Excessive surface roughness or scratches can produce signals that interfere with the test. 6. Apparatus 6.1 The instruments and accessory equipment shall be of the pulse-reflection type and shall be capable of distinguishing the reference notches described in Section 8 to the extent required in the calibration procedure described in Section 9. Figure 1 illustrates the characteristic oblique entry of sound into the pipe or tube wall, and the circumferential direction of ultrasonic energy propagation used to detect longitudinal notches. 7. Couplant 7.1 A liquid couplant such as water, oil, or glycerin, capable of conducting ultrasonic vibrations between the transducer and the pipe or tube being tested shall be used. Rust inhibitors, softeners, and wetting agents may be added to the couplant. The couplant liquid with all additives should not be detrimental to the surface condition of the pipe or tube, and shall wet the surface of the material to provide adequate coupling efficiency. NOTE 1 In contact testing, some couplants result in better ultrasonic transmission when the tubing is precoated several hours before the test. 8. Calibration Standards 8.1 A calibration (reference) standard of a convenient length shall be prepared from a length of pipe or tube of the same nominal diameter, wall thickness, material, surface finish, and heat treatment as the material to be inspected. The calibration pipe or tube shall be free of discontinuities or other conditions producing indications that can interfere with detection of the reference notches. 8.2 Longitudinal (axial) reference notches shall be introduced on the outer and inner surfaces of the standard. 8.3 If two or more reference notches are placed on the same end of the calibration standard, they shall be separated sufficiently (circumferentially or axially or both) to preclude interference and interpretation difficulties. 8.4 All upset metal, burrs, etc., adjacent to the reference notches shall be removed. 8.5 The notch dimensions, which are length, depth, and width (and for V-notches, the included angle) shall be specified in agreements between the purchaser and supplier. Figure 2 illustrates the common notch configurations and the dimensions to be measured (Note 2). Reflection amplitudes from V-, square-, and U-shaped notches of comparable dimensions may vary widely depending on the angle, frequency, and vibrational mode of the interrogating sound beam. NOTE 2 In Figures 2 (a), (b), and (d), the sharp corners are for ease of illustration. It is recognized that in normal machining practice, a radius will be generated The notch depth shall be an average measured from the circular tubing surface to the maximum and minimum penetration of the notch. Measurements may be made by optical, replicating, or other mutually agreed upon techniques. Notch depth shall be within in. (0.13 mm) or less in depth, and within +10, 15% of the specified value for notches over in. in depth. NOTE 3 For as-rolled or scaly tube surfaces, it may be necessary to modify Two acceptable modifications are listed below. Modification (1) is preferred; however, modification (2) may be used unless otherwise specified by the purchaser. (1) The circular tube surface may be smoothed or prepared in the notch area, or (2) The notch depth shall be within in. (0.025 mm), or +10, 15% of the specified depth, whichever is greater The width of the notches shall be as small as practical, but should not exceed twice the depth. 8.6 Other types and orientations of reference discontinuities may be specified upon contractual agreement between the purchaser and the supplier. 9. Calibration of Apparatus 9.1 Using the calibration standard specified in Section 8, adjust the equipment to produce clearly identifiable indications from both the inner and outer surface 454

63 SE-213 ARTICLE 23 ULTRASONIC STANDARDS SE-213 notches. The relative response from the inner and outer surface notches shall be as nearly equal as possible. Use the lesser of the two responses to establish the rejection level. On large diameter or heavy wall pipe and tubing, if the inner and outer surface notch amplitude cannot be made equal because of test metal distance and inside diameter curvature, a separate rejection level may be established for the inner and outer surface notches. NOTE 4 Indication amplitude may not be proportional to notch depth. 9.2 Calibrate the equipment under dynamic conditions that simulate the production inspection. The pipe or tubing to be inspected and the search unit assembly shall have a rotating translating motion relative to each other such that a helical scan path will be described on the outer surface of the pipe or tube. Maintain the speed of rotation and translation constant within 10%. Axial scanning with circumferential indexing may be used to provide equivalent coverage. 9.3 The pitch of the feed helix shall be small enough to ensure 100% coverage at the test distance and sensitivity established during calibration and may be subject to agreement between the purchaser and supplier. 10. Procedure 10.1 Unless otherwise specified, inspect the pipe or tubing with the ultrasound transmitted in one circumferential direction under the identical conditions used for equipment calibration (Note 5). Upon contractual agreement between the purchaser and supplier, inspection may be required with the ultrasound transmitted in both circumferential directions (see Supplementary Requirement S1). If the inspection is to be performed in both directions, conduct the calibration procedure of Section 9 in both directions. NOTE 5 Identical conditions shall include all instrument settings, mechanical motions, search unit attitude, and position relative to the pipe or tube, liquid couplant, and any other factors that affect the performance of the inspection Periodically check calibration of the equipment by passing the calibration standard through the inspection equipment. Make these checks prior to any inspection run, prior to equipment shutdown after an inspection run, and at least every 4 h during continuous equipment operation. Recalibrate the equipment in accordance with Section 9 any time the equipment does not present a clearly defined, rejectable signal from both the inner and outer surface notches of the standard For many tubular sizes and inspection arrangements, there will be a reflection from the entry surface of the pipe or tube. This signal may be observed, but not gated, as a supplement to the required checking of the calibration standard to give increased assurance that the equipment is functioning properly. If such a signal does not exist, make more frequent equipment calibration checks In the event that the equipment does not present signals as outlined in 9.1 and 10.2, reinspect all pipe or tubing tested since the last acceptable calibration after recalibration has been accomplished Do not make any equipment adjustments unless the complete calibration procedure described in Section 9 is performed The inspection shall be applied to 100% of the pipe or tubing unless otherwise specified. NOTE 6 Some traversing mechanisms do not allow inspection of tubing ends. When this condition exists, clearly indicate the extent of this effect, per tube, in the inspection report. 11. Interpretation of Results 11.1 All indications that are equal to or greater than the rejection level established during calibration as described in Section 9, or as specified in the procurement contract, shall be considered as representing defects and may be cause for rejection of the pipe or tube If, upon examination of the pipe or tube, no rejectable indications are detected, the material shall be considered as having passed the ultrasonic examination, except as noted in NOTE 7 Rejected pipe or tubes may be reworked in a manner acceptable to the purchaser. If, upon ultrasonic reexamination of the reworked pipe or tube, no rejectable indications are detected, the material should be considered as having passed the ultrasonic inspection. NOTE 8 Care should be exercised to assure that reworking a pipe or tube does not change its acceptability with respect to other requirements of the material specification such as wall thickness, ovality, surface finish, length, etc. 12. Report 12.1 Upon request, the supplier shall submit to the purchaser such information as is mutually considered adequate to document that the pipe or tubes supplied meet the requirements of this recommended practice. 455

64 SE SECTION V SE-213 SUPPLEMENTARY REQUIREMENTS These requirements shall apply only when individually specified by the purchaser. When details of these requirements are not covered herein, they are subject to agreement between the purchaser and the supplier. S1. Scanning S1.1 When specified, scanning shall be conducted in both circumferential directions. S2. Distance Amplitude Correction S2.1 A method of compensating for the reduction in ultrasonic signal amplitude as a function of test metal distance shall be employed. Details of the procedures used to establish and apply the distance amplitude correction (DAC) curve shall be subject to agreement between the purchaser and the supplier. S4. Recording S4.1 When specified, a permanent record containing objective evidence of the examination results shall accompany each accepted pipe or tube. This will normally be in the form of a strip chart recording of the ultrasonic instrument output during the inspection. It shall contain recordings of all calibrations and calibration checks and shall be annotated to provide a positive correlation between each test record and the corresponding pipe and tube. S3. Transverse Notches S3.1 Instead of (or in addition to) the longitudinal notches described in Section 8, a transverse (circumferential) notch shall be introduced on the inner and outer surfaces of the calibration standard. The requirements of 8.3, 8.4, and 8.5 shall apply to transverse notches. S3.2 An independent channel of instrumentation (including search unit assembly) shall be employed for the purpose of detecting transverse discontinuities. S3.3 When transverse notches are specified, the agreement between the purchaser and the supplier shall also specify whether scanning is required in one or both axial directions. Figure 3 illustrates the characteristic oblique entry of sound into the pipe or tube wall, and the axial propagation of ultrasonic energy to detect transverse notches. NOTE 9 If the specification requires both longitudinal and transverse notches, and scanning in both longitudinal and both axial directions, the following three options are available: (a) Each pipe or tube is passed through a single channel inspection station four times, twice in each direction, (b) Each pipe or tube is passed through a two-channel inspection station twice, once in each direction, or (c) Each pipe or tube is passed through a four-channel inspection station once. S5. Report S5.1 When specified, the supplier shall submit to the purchaser an inspection report that includes at least the following information: S5.1.1 Identification of the material by type, size, lot, heat, etc. S5.1.2 Identification of the inspection equipment and accessories. S5.1.3 Details of the inspection technique, including inspection speed, testing frequency, and end effects if any (Note 9). S5.1.4 Description of the calibration standard, including the actual (measured) dimensions of the artificial discontinuities. S5.1.5 Description of the distance amplitude correction procedure, if used. (See Supplementary Requirement S2.) S5.1.6 Inspection results. 456

65 SE-213 ARTICLE 23 ULTRASONIC STANDARDS SE-213 FIG. 1 CIRCUMFERENTIAL PROPAGATION OF SOUND IN TUBE WALL FIG. 2 COMMON NOTCH SHAPES 457

66 SE SECTION V SE-213 FIG. 3 AXIAL PROPAGATION OF SOUND IN TUBE WALL 458

67 SE-214 ARTICLE 23 ULTRASONIC STANDARDS SE-214 STANDARD PRACTICE FOR IMMERSED ULTRASONIC EXAMINATION BY THE REFLECTION METHOD USING PULSED LONGITUDINAL WAVES SE-214 [Identical with ASTM E (1985) 1 ] 1. Scope 1.1 This practice describes in general terms an ultrasonic test procedure for detecting discontinuities in material using testing instruments which have been designed to transmit and receive pulsed longitudinal ultrasonic waves introduced into the material to be inspected through a liquid coupling agent. 3. Application 3.1 This procedure applies to any material that can conduct sound waves of an appropriate frequency, and can be immersed in a liquid coupling agent for inspection, or can be subject to inspection by the use of a column or stream of the couplant through an appropriate container attached to the part or transducer. NOTE 1 Practice E 1001 is a complementary document that extends Practice E 214 by describing more detailed procedures. 1.2 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of whoever uses this standard to consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 4. Apparatus 4.1 Electronic Apparatus The electronic apparatus shall be capable of producing, receiving, and displaying high-frequency electrical pulses at the required frequency and energy levels, and employ A-Scan; time base versus magnitude (Note 2). The instrument used should provide stable amplification of received pulses at the required test sensitivity levels. An appropriate line-voltage regulating transformer shall be used, if required, to ensure maximum stability. NOTE 2 Other presentations, such as B-Scan and C-Scan, are available but are not covered in this practice. 2. Applicable Documents 2.1 ASTM Standards: E 127 Practice for Fabricating and Checking Aluminum Alloy Ultrasonic Standard Reference Blocks E 428 Recommended Practice for Fabrication and Control of Steel Reference Blocks Used in Ultrasonic Inspection E 1001 Practice for Detection and Evaluation of Discontinuities by the Immersed Pulse-Echo Ultrasonic Method Using Longitudinal Waves 4.2 Immersion Search Units Immersible transducers for transforming electrical impulses into sound vibrations and vice versa, at the appropriate frequencies and energy levels shall be used. The transducers shall be capable of transmitting and receiving ultrasound to and from the immersed test specimen. 4.3 Couplant The couplant, a liquid such as water, oil, glycerin, etc., capable of conducting ultrasonic vibrations from the transducer to the material being tested shall be used. Rust inhibitors, softeners, and 459

68 SE SECTION V SE-214 wetting agents may be added to the couplant. The couplant liquid with all additives should not be detrimental to the surface condition of the test specimen or the container, and should wet the surface of the material to provide an intimate contact. Couplant may be heated to a comfortable working temperature and must be free of air bubbles. 4.4 Manipulator The holder for the search tube and search unit that provides angular manipulation of the transducer for optimum response from the internal discontinuities. The maximum tolerance or play allowable in the manipulator and in the traversing unit should be adequate to permit ultrasonic testing at the sensitivity specified. 4.5 Accessory Equipment Coaxial cables and search tubes used in conjunction with the electronic apparatus capable of conducting the electrical pulses while immersed in a liquid, and collimators for shaping the sound beam shall be used. 4.6 Reference Blocks In order to correct for the many variables involved in ultrasonic testing, it is necessary to use references to establish instrument settings, assist reproducibility of techniques, and evaluate discontinuities. The fabrication of reference blocks should be governed by the requirements described in Practices E 127 or E Calibration of Apparatus 5.1 Prior to inspection, it is recommended that the ultrasonic system be standardized by means of ASTM reference blocks as specified in the product specification. The equipment should be operated with the reference hole signal amplitude in the range between 25% above the noise level and below the saturation level (usually between 25 and 75% of full screen height). As an alternative, a system sensitivity may be established by adjusting the height of the first back reflection or number of multiple back reflections over an ultrasonically clean area as specified in the product specification. 5.2 If reference blocks are used, they should have ultrasonic characteristics, such as attenuation, noise level, and velocity similar to the metal being tested, or suitable correction should be made. 5.3 Ultrasonic characteristics should be evaluated by comparison of unsaturated first back-surface reflection or back-surface pattern from material tested with that of the reference standard with similar surface conditions, for example roughness and angularity. Any reduction of the back-reflection pattern is indicative of increased attenuation or loss of transmitted energy due to absorption or scatter within the material being tested, provided front- and back-surface roughness and parallelism of the test piece are approximately the same as that of the standard. In this case, correction for differences in acoustical properties should be made. 5.4 The distance between transducer and work should be adjusted to suit the particular size, type, and frequency of the transducer being used. However, in no case should the couplant distance allow an entry surface signal or first interface signal to interfere with the first order metal-travel distance in the A-scan presentation. The transducer-work couplant distance should be held equal, within 1 4 in. (6.4 mm), to that established with the related reference standard. 5.5 Reference standards should be spot-checked at least hourly to ensure that the ultrasonic system calibration is not drifting. 6. Procedure 6.1 Testing Surface Surfaces shall be uniform and free of loose scale machining or grinding particles, discontinuities such as pits or gouges, or foreign matter. In the case of steel, scale reasonably smooth and securely bonded to the metal need not be removed for testing. The surface must be adequate to permit ultrasonic inspection at the sensitivity specified. 6.2 Test Frequency Select a suitable test frequency after due consideration of the material thickness and the minimum discontinuity that is to be detected, plus the attenuation factor of the material to be tested. Theoretically, the higher the frequency, the smaller the detectable discontinuity. However, increasing attenuation, noise level, and surface conditions may be a limiting factor at higher frequencies. 6.3 Scanning The transducer may be hand-held, in which case use some guide such as a plastic tube in order to hold the transducer-part distance and geometrical relationship constant. For mechanical scanning, the transducer may be mounted in a search tube that is held in a manipulator or fixture and moved over the surface of the part being tested by some mechanical means. When appropriate, the part may be moved past a fixed transducer. The scanning may be continuous or intermittent over designated areas as outlined by the requirements of design and specification of the part. For continuous scanning, the transducer indexing must be adequate to provide 100% coverage at the test sensitivity and test distance. Select a scanning speed 460

69 SE-214 ARTICLE 23 ULTRASONIC STANDARDS SE-214 such as to permit detection of the smallest discontinuities referenced in the specification and slow enough to allow any recording or signaling device to function. 6.4 Make evaluation of ultrasonic indications after reflections are maximized by angular manipulation of the transducer over the indication. In the case of scanning by hand or using some device other than a rigidly mounted manipulator, the transducer-work couplant distance should be carefully maintained as referenced under Section Establish the scanning of the material being inspected so that volumes to be tested are adequately penetrated by the sonic beam. Determine the suitability of reference test blocks for evaluating the ultrasonic indications by the similarity in attenuation and velocity between reference standards and the material being tested. In general, reference standards from one wrought aluminum alloy are representative of most wrought aluminum alloys, and 4130 or 4340 steel alloy standards are representative of most low-alloy carbon steels. Consider any significant difference in attenuation between reference standards and the part or material being tested during the scanning procedure, and make corrections in interpretations of the reflection amplitudes for differences in attenuation. 7. Test Data Record 7.1 The following data should be recorded at the time of each test for future reference: Date and part number for identification, Inspector, Type of instrument, make, model, and serial number, Test frequency, Transducer type and effective beam size, collimator, cable length, tuning network, and water travel, References, Amplitude or response from the discontinuities of a known size in the reference blocks used and back-reflection information (attenuation) from same. If other references are used, a statement of procedure should be included Results of test (number, classification, and location of discontinuities). 8. Interpretation of Results 8.1 Internal discontinuities may be located and their estimated magnitude established by the foregoing procedure. The results and subsequent action shall be agreed upon by the purchaser and material supplier as part of the job requirements. 9. Report 9.1 The report should reference this practice and applicable test parameters agreed upon with the material supplier in order that the result of different testing groups can be correlated. 9.2 Parts meeting the quality requirements agreed upon between the purchaser and the manufacturer should be identified and listed as required, and certified as to meeting the applicable specification requirements. 9.3 Parts that will have to be handled through action by an agency such as the aircraft industries Material Review Board or other discrepant procedure shall be completely recorded with ultrasonic information showing size and location of discontinuities accompanied by a sketch showing the size and location of the indications. 461

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71 SE-273 ARTICLE 23 ULTRASONIC STANDARDS SE-273 STANDARD PRACTICE FOR ULTRASONIC EXAMINATION OF LONGITUDINAL WELDED PIPE AND TUBING SE-273 (Identical with ASTM Specification E ) 1. Scope 1.1 This practice describes general ultrasonic test procedures for the detection of discontinuities in the weld and adjacent heat affected zones of pipe and tubing. It is intended for tubular products having diameters 2 in. ( 50 mm) and wall thicknesses of 1 8 to in. (3 to 27 mm). 1.2 This practice does not establish acceptance criteria; they must be specified by the using parties. NOTE 1 Precautions should be exercised when testing pipes or tubes near the lower specified limits. Certain combinations of search unit size, frequency, thin wall thicknesses, and small diameters could cause generation of unwanted sound waves that may produce erroneous test results. 1.3 The values stated in inch-pound units are to be regarded as the standard. 2. Applicable Document 2.1 ASTM Standard: E 500 Definitions of Terms Relating to Ultrasonic Testing 3. Summary of Method 3.1 Angle projection of pulsed ultrasonic beam by either the surface contact or immersion method shall be used. Figure 1 illustrates the characteristic oblique sound entry into the pipe wall for both contact and immersion testing using a single search unit. NOTE 2 Immersion test method may include tanks, wheel search units, or bubbler systems. 3.2 Variations of the single search unit method using multiple search units with the same or various angles and special gating are sometimes desirable and may be necessary for efficient examination of thicker wall material. 4. Apparatus 4.1 The instruments and accessory equipment shall be capable of producing, receiving, amplifying, and displaying electrical pulses at frequencies and pulse rates deemed necessary by the using parties. They shall be capable of distinguishing the reference reflectors described in Section 6 to the extent required in the calibration procedure outlined in Section For pulse echo test systems, the contact or immersion search units should produce ultrasonic waves that travel in the pipe or tube wall at a refracted angle of from 35 to 70 and perpendicular to the weld seam. For pitch/catch or through transmission test systems, orientation of the entry sound beam other than perpendicular to the weld seam may be required. 4.3 Couplant A liquid such as water, oil, glycerin, etc., capable of conducting ultrasonic vibrations from the transducer to the pipe or tube shall be used. Rust inhibitors, softeners, and wetting agents may be added to the couplant. The couplant liquid with all additives should not be detrimental to the surface condition of the pipe or tubing and should wet the surface. In the testing of electric-resistance-welded pipe, water-soluble oil used in cooling the pipe serves as a satisfactory couplant. 463

72 SE SECTION V SE-273 FIG. 1 ANGLE PROJECTION OF ULTRASONIC WAVE 4.4 Distance Amplitude Compensation The use of electronic methods to compensate for attenuation losses as a function of ultrasonic metal travel distance may be employed. 5. Basis of Application 5.1 The following are items that require decision for use of this practice: Acceptance criteria, Type, dimension, and number of reference reflectors to be placed in the reference standard, Standardization of test sensitivity intervals, Operator qualifications, Test frequency, Pulse repetition rate, Sound beam orientation and number of beams used, Procedure and use of distance amplitude compensation, and Reporting of test results. 6. Personnel Qualification 6.1 The ultrasonic examination shall be performed by qualified personnel. Qualification shall be based on a documented program that certifies personnel capable of conducting ultrasonic weld examinations. 7. Reference Standards 7.1 A reference standard, of sufficient length to allow verification of system calibration, shall be prepared from a length of pipe or tubing of the same nominal diameter and wall thickness, material, surface finish, and nominal heat treatment as the material to be examined. The pipe or tube selected for this purpose shall be free of discontinuities or other abnormal conditions that can cause interference with the detection of the reference reflectors. The reference reflectors shall be selected to ensure uniform coverage of the weld at the sensitivity levels prescribed. The reference reflectors most commonly used will consist of machined notches and drilled holes as described in paragraph 7.2. All upset metal, burrs, etc., adjacent to the reference reflectors, shall be removed Electric Resistance-Welded or Butt-Welded Pipe Reference reflectors may be placed in the weld seam or in the pipe body and parallel to the weld seam. When longitudinal notches are used as reference reflectors, they shall be placed on the outer and inner surfaces of the reference standard and separated by some distance to ensure that the response from one reflector does not interfere with that from the other Fusion-Welded Pipe The reference reflectors shall be placed in the weld. When longitudinal notches are used as reference reflectors, they shall be placed in the crown of the fusion-weld bead as shown in Fig. 2(a). In fusion-welded pipe containing both inside and outside surface weld beads, a longitudinal notch reference reflector shall be placed in the weldbead crown on both the outside and inside surfaces When drilled holes are employed, they shall be drilled radially from both the outside and inside surfaces through 50% of the wall thickness at the weld-bead crown and separated by some distance that guarantees a distinct and separate response from each one [see Figs. 2(c) and 2(d)]. A hole drilled radially 100% through the pipe wall may be used instead of the 50% drilled hole [see Fig. 2(e)]. 464

73 SE-273 ARTICLE 23 ULTRASONIC STANDARDS SE-273 FIG. 2 TYPICAL NOTCH LOCATIONS FOR FUSION WELDED PIPE Additional reflectors may be used to define weld extremities. Holes shall be drilled radially 100% through the pipe wall at the weld edges. As an alternative, longitudinal notches shall be placed at the edges of each weld [see Fig. 2(f)]. The weld-edge drilled holes or notches shall be separated by some distance to ensure that the response from one reflector does not interfere with that from another (see Fig. 2(g)). The weld-edge reflectors are solely for the purpose of defining the position of the weld extremities and are not to be used for amplitude standardization. 7.2 The notch dimension of length, decided depth, width, and for Figs. 3(a) and 3(b) the included angle must be decided upon by the using party or parties. Figure 3 illustrates the commonly accepted notch configurations and the dimensions to be measured The notch depth (h) shall be measured from the adjacent surface to its maximum and minimum penetration. Measurements may be made by optical, replicating or mechanical, or other techniques. Notch depth is commonly specified as a percent of nominal wall thickness with typical values being 10, ,or 20%. A 15% tolerance is allowable on notch depths The length of the notch is considered to be the dimension where the depth of is satisfied. It is preferred that the notch length (l) be 1.5 times the transducer element size The width (w) of the notch has negligible effect on calibration and is not a critical dimension Typical diameters for drilled holes are 1 16 in. (1.6 mm) and 1 8 in. (3.2 mm). 8. Standardization of Test Sensitivity 8.1 Using the reference standard specified in 7.1, the equipment shall be adjusted to produce readily distinguished and clearly identifiable indications from both the inner and outer reference reflectors. The relative response to the inner and outer reflectors shall be as near equal as possible. The lesser of the two responses shall be used as the acceptance level. NOTE 3 Adjustment of water path, adjustment of distance (d) in Fig. 1 and angulation of the beam have been used to achieve equality. 8.2 The test sensitivity shall be standardized and adjusted to produce clearly identifiable indications from both the outer and inner reference reflectors when the reference standard is scanned in a manner simulating the production examination of the pipe or tubing. 465

74 SE SECTION V SE-273 FIG. 3. COMMON REFERENCE REFLECTORS 8.3 The equipment shall be adjusted to produce clearly identifiable responses from the weld-edge reflector and the reference reflector when the reference standard is scanned in a manner simulating the production examination of the pipe or tubing. 9. Examination Procedure 9.1 All surfaces shall be clean from scale, dirt, burrs, slag, spatter, or other conditions that will interfere with the test results. 9.2 Move the pipe or tubing past the search unit with the weld in a fixed position with respect to the search unit. Movement of the search unit with respect to a stationary pipe is satisfactory. During examination, maintain distance (d) and angle in Fig. 1 and the water path for immersion testing as determined during adjustment of the test sensitivity. 9.3 Certain testing systems using multiple search units or multiple beam transducers compensate for distance (d) changes and do not require strict adherence to the maintenance of this dimension during examination. 9.4 Periodically check the test sensitivity of the equipment by running the reference standard through the examination system. Make these checks prior to any pipe or tubing examination, prior to equipment shutdown after examination and at least every four hours during continuous equipment operation. Any time the equipment does not present a clearly defined signal within 10% of that obtained when the test sensitivity was established, readjust the equipment in accordance with Section In the event that the equipment presents a signal less than 10% below the standardization level, reexamine, when standardization has been accomplished, all pipe and tubing examined subsequent to the last preceding acceptable standardization. 10. Interpretation of Results 10.1 All indications that are equal to or greater than the reference signals established during standardization as described in Section 8, or as specified in Section 5, shall be considered as representing defects that may be cause for rejection of the pipe or tube If upon examination of the pipe or tube, no rejectable indications are detected, the material shall be considered as having passed the ultrasonic examination, except as noted in

75 SE-797 ARTICLE 23 ULTRASONIC STANDARDS SE-797 STANDARD PRACTICE FOR MEASURING THICKNESS BY MANUAL ULTRASONIC PULSE- ECHO CONTACT METHOD 1 98 SE-797 (Identical with ASTM E ) 1. Scope 1.1 This practice 2 provides guidelines for measuring the thickness of materials using the contact pulse-echo method at temperatures not to exceed 200 F (93 C). 1.2 This practice is applicable to any material in which ultrasonic waves will propagate at a constant velocity throughout the part, and from which back reflections can be obtained and resolved. 1.3 The values stated in either inch-pound or SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Referenced Documents 2.1 ASTM Standards: E 317 Practice for Evaluating Performance Characteristics of Ultrasonic Pulse-Echo Testing Systems Without the Use of Electronic Measurement Instruments 3 1 This practice is under the jurisdiction of ASTM Committee E-7 on Nondestructive Testing and is the direct responsibility of Subcommittee E07.06 on Ultrasonic Testing Procedure. Current edition approved Dec. 10, Published February Originally published as E Last previous edition E For ASME Boiler and Pressure Vessel Code applications, see related Practice SE-797 in Section II of that Code. 3 Annual Book of ASTM Standards, Vol E 494 Practice for Measuring Ultrasonic Velocity in Materials 3 E 1316 Terminology for Nondestructive Examinations ASNT Document: Nondestructive Testing Handbook, 2nd Edition, Vol Terminology 3.1 Definitions For definitions of terms used in this practice, refer to Terminology E Summary of Practice 4.1 Thickness (T), when measured by the pulse-echo ultrasonic method, is a product of the velocity of sound in the material and one half the transit time (round trip) through the material. where: T p thickness, V p velocity, and t p transit time. T p Vt The pulse-echo ultrasonic instrument measures the transit time of the ultrasonic pulse through the part. 4 Available from the American Society for Nondestructive Testing, 1711 Arlingate Plaza, Columbus, OH

76 SE SECTION V SE The velocity in the material under test is a function of the physical properties of the material. It is usually assumed to be a constant for a given class of materials. Its approximate value can be obtained from Table X3.1 in Practice E 494 or from the Nondestructive Testing Handbook, or it can be determined empirically. 4.4 One or more reference blocks are required having known velocity, or of the same material to be tested, and having thicknesses accurately measured and in the range of thicknesses to be measured. It is generally desirable that the thicknesses be round numbers rather than miscellaneous odd values. One block should have a thickness value near the maximum of the range of interest and another block near the minimum thickness. 4.5 The display element [CRT (cathode ray tube), meter, or digital display] of the instrument must be adjusted to present convenient values of thickness dependent on the range being used. The control for this function may have different names on different instruments, including range, sweep, material calibrate, or velocity. 4.6 The timing circuits in different instruments use various conversion schemes. A common method is the so-called time/analog conversion in which the time measured by the instrument is converted into a proportional dc voltage which is then applied to the readout device. Another technique uses a very high-frequency oscillator that is modulated or gated by the appropriate echo indications, the output being used either directly to suitable digital readouts or converted to a voltage for other presentation. A relationship of transit time versus thickness is shown graphically in Fig Significance and Use 5.1 The techniques described provide indirect measurement of thickness of sections of materials not exceeding temperatures of 200 F (93 C). Measurements are made from one side of the object, without requiring access to the rear surface. 5.2 Ultrasonic thickness measurements are used extensively on basic shapes and products of many materials, on precision machined parts, and to determine wall thinning in process equipment caused by corrosion and erosion. 5.3 Recommendations for determining the capabilities and limitations of ultrasonic thickness gages for specific applications can be found in the cited references. 5,6 6. Apparatus 6.1 Instruments Thickness-measurement instruments are divided into three groups: (1) Flaw detectors with CRT readout, (2) Flaw detectors with CRT and direct thickness readout, and (3) Direct thickness readout Flaw detectors with CRT readouts display time/amplitude information in an A-scan presentation. Thickness determinations are made by reading the distance between the zero-corrected initial pulse and first-returned echo (back reflection), or between multiple-back reflection echoes, on a calibrated base line of a CRT. The base line of the CRT should be adjusted for the desired thickness increments Flaw detectors with numeric readout are a combination pulse ultrasound flaw detection instrument with a CRT, and additional circuitry that provides digital thickness information. The material thickness can be electronically measured and presented on a digital readout. The CRT provides a check on the validity of the electronic measurement by revealing measurement variables, such as internal discontinuities, or echo-strength variations, which might result in inaccurate readings Thickness readout instruments are modified versions of the pulse-echo instrument. The elapsed time between the initial pulse and the first echo or between multiple echoes is converted into a meter or digital readout. The instruments are designed for measurement and direct numerical readout of specific ranges of thickness and materials. 6.2 Search Units Most pulse-echo type search units (straight-beam contact, delay line, and dual element) are applicable if flaw detector instruments are used. If a thickness readout instrument has the capability to read thin sections, a highly damped, high-frequency search unit is generally used. High-frequency (10 MHz or higher) delay line search units are generally required for thicknesses less than about 0.6 mm (0.025 in.). 5 Bosselaar, H. and Goosens, J.C.J., Method to Evaluate Direct- Reading Ultrasonic Pulse-Echo Thickness Meters, Materials Evaluation, March 1971, pp Fowler, K.A., Elfbaum, G.M., Husarek, V., and Castel, J., Application of Precision Ultrasonic Thickness Gaging, Proceedings of the Eighth World Conference on Nondestructive Testing, Cannes, France, Sept. 6 11, 1976, Paper 3F

77 SE-797 ARTICLE 23 ULTRASONIC STANDARDS SE-797 FIG. 1 TRANSIT TIME/THICKNESS RELATIONSHIP Measurements of materials at high temperatures require search units specially designed for the application. When dual element search units are used, their inherent nonlinearity usually requires special corrections for thin sections (see Fig. 2.) For optimum performance, it is often necessary that the instrument and search units be matched. 6.3 Calibration Blocks The general requirements for appropriate calibration blocks are given in 4.4, 7.1.3, , 7.3.2, and Multi-step blocks that may be useful for these calibration procedures are described in Appendix XI (Figs. X1.1 and X1.2). 7. Procedure Calibration and Adjustment of Apparatus 7.1 Case I Direct Contact, Single-Element Search Unit: Conditions The display start is synchronized to the initial pulse. All display elements are linear. Full thickness is displayed on CRT Under these conditions, we can assume that the velocity conversion line effectively pivots about the origin (Fig. 1). It may be necessary to subtract the wear-plate time, requiring minor use of delay control. It is recommended that test blocks providing a minimum of two thicknesses that span the thickness range be used to check the full-range accuracy Place the search unit on a test block of known thickness with suitable couplant and adjust the instrument controls (material calibrate, range, sweep, or velocity) until the display presents the appropriate thickness reading The readings should then be checked and adjusted on test blocks with thickness of lesser value to improve the overall accuracy of the system. 7.2 Case II Delay Line Single-Element Search Unit: Conditions When using this search unit, it is necessary that the equipment be capable of correcting for the time during which the sound passes through the delay line so that the end of the delay can be made to coincide with zero thickness. This requires a socalled delay control in the instrument, or automatic electronic sensing of zero thickness In most instruments, if the material calibrate circuit was previously adjusted for a given material velocity, the delay control should be adjusted until a 469

78 SE SECTION V SE-797 FIG. 2 DUAL TRANSDUCER NONLINEARITY 470

79 SE-797 ARTICLE 23 ULTRASONIC STANDARDS SE-797 correct thickness reading is obtained on the instrument. However, if the instrument must be completely calibrated with the delay line search unit, the following technique is recommended: Use at least two test blocks. One should have a thickness near the maximum of the range to be measured and the other block near the minimum thickness. For convenience, it is desirable that the thickness should be round numbers so that the difference between them also has a convenient round number value Place the search unit sequentially on one and then the other block, and obtain both readings. The difference between these two readings should be calculated. If the reading thickness difference is less than the actual thickness difference, place the search unit on the thicker specimen, and adjust the material calibrate control to expand the thickness range. If the reading thickness difference is greater than the actual thickness difference, place the search unit on the thicker specimen, and adjust the material calibrate control to decrease the thickness range. A certain amount of over correction is usually recommended. Reposition the search unit sequentially on both blocks, and note the reading differences while making additional appropriate corrections. When the reading thickness differential equals the actual thickness differential, the material thickness range is correctly adjusted. A single adjustment of the delay control should then permit correct readings at both the high and low end of the thickness range An alternative technique for delay line search units is a variation of that described in A series of sequential adjustments are made, using the delay control to provide correct readings on the thinner test block and the range control to correct the readings on the thicker block. Moderate over-correction is sometimes useful. When both readings are correct the instrument is adjusted properly. 7.3 Case III Dual Search Units: The method described in 7.2 (Case II) is also suitable for equipment using dual search units in the thicker ranges, above 3 mm (0.125 in.). However, below those values there is an inherent error due to the Vee path that the sound beam travels. The transit time is no longer linearly proportional to thickness, and the condition deteriorates toward the low thickness end of the range. The variation is also shown schematically in Fig. 2(a). Typical error values are shown in Fig. 2(b) If measurements are to be made over a very limited range near the thin end of the scale, it is possible to calibrate the instrument with the technique in Case II using appropriate thin test blocks. This will produce a correction curve that is approximately correct over that limited range. Note that it will be substantially in error at thicker measurements If a wide range of thicknesses is to be measured, it may be more suitable to calibrate as in Case II using test blocks at the high end of the range and perhaps halfway toward the low end. Following this, empirical corrections can be established for the very thin end of the range For a direct-reading panel-type meter display, it is convenient to build these corrections into the display as a nonlinear function. 7.4 Case IV Thick Sections: Conditions For use when a high degree of accuracy is required for thick sections Direct contact search unit and initial pulse synchronization are used. The display start is delayed as described in All display elements should be linear. Incremental thickness is displayed on the CRT Basic calibration of the sweep will be made as described in Case I. The test block chosen for this calibration should have a thickness that will permit calibrating the full-sweep distance to adequate accuracy, that is, about 10 mm (0.4 in.) or 25 mm (1.0 in.) full scale After basic calibration, the sweep must be delayed. For instance, if the nominal part thickness is expected to be from 50 to 60 mm (2.0 to 2.4 in.), and the basic calibration block is 10 mm (0.4 in.), and the incremental thickness displayed will also be from 50 to 60 mm (2.0 to 2.4 in.), the following steps are required. Adjust the delay control so that the fifth back echo of the basic calibration block, equivalent to 50 mm (2.0 in.), is aligned with the 0 reference on the CRT. The sixth back echo should then occur at the right edge of the calibrated sweep This calibration can be checked on a known block of the approximate total thickness The reading obtained on the unknown specimen must be added to the value delayed off screen. For example, if the reading is 4 mm (0.16 in.), the total thickness will be 54 mm (2.16 in.). 471

80 SE SECTION V SE Technical Hazards 8.1 Dual search units may also be used effectively with rough surface conditions. In this case, only the first returned echo, such as from the bottom of a pit, is used in the measurement. Generally a localized scanning search is made to detect the minimum remaining wall. 8.2 Material Properties The instrument should be calibrated on a material having the same acoustic velocity and attenuation as the material to be measured. Where possible, calibration should be confirmed by direct dimensional measurement of the material to be examined. 8.3 Scanning The maximum speed of scanning should be stated in the procedure. Material conditions, type of equipment, and operator capabilities may require slower scanning. 8.4 Geometry: Highest accuracy can be obtained from materials with parallel or concentric surfaces. In many cases, it is possible to obtain measurements from materials with nonparallel surfaces. However, the accuracy of the reading may be limited and the reading obtained is generally that of the thinnest portion of the section being interrogated by the sound beam at a given instant Relatively small diameter curves often require special techniques and equipment. When small diameters are to be measured, special procedures including additional specimens may be required to ensure accuracy of setup and readout. 8.5 High-temperature materials, up to about 540 C (1000 F), can be measured with specially designed instruments with high temperature compensation, search unit assemblies, and couplants. Normalization of apparent thickness reading for elevated temperatures is required. A rule of thumb often used is as follows: The apparent thickness reading obtained from steel walls having elevated temperatures is high (too thick) by a factor of about 1% per 55 C (100 F). Thus, if the instrument was calibrated on a piece of similar material at 20 C (68 F), and if the reading was obtained with a surface temperature of 460 C (860 F), the apparent reading should be reduced by 8%. This correction is an average one for many types of steel. Other corrections would have to be determined empirically for other materials. 8.6 Instrument Time base linearity is required so that a change in the thickness of material will produce a corresponding change of indicated thickness. If a CRT is used as a readout, its horizontal linearity can be checked by using Practice E Back Reflection Wavetrain Direct-thickness readout instruments read the thickness at the first half cycle of the wavetrain that exceeds a set amplitude and a fixed time. If the amplitude of the back reflection from the measured material is different from the amplitude of the back reflection from the calibration blocks, the thickness readout may read to a different half cycle in the wavetrain, thereby producing an error. This may be reduced by: Using calibration blocks having attenuation characteristics equal to those in the measured material or adjusting back reflection amplitude to be equal for both the calibrating blocks and measured material Using an instrument with automatic gain control to produce a constant amplitude back reflection. 8.8 Readouts CRT displays are recommended where reflecting surfaces are rough, pitted, or corroded Direct-thickness readout, without CRT, presents hazards of misadjustment and misreading under certain test conditions, especially thin sections, rough corroded surfaces, and rapidly changing thickness ranges. 8.9 Calibration Standards Greater accuracy can be obtained when the equipment is calibrated on areas of known thickness of the material to be measured Variations in echo signal strength may produce an error equivalent to one or more half-cycles of the RF frequency, dependent on instrumentation characteristics. 9. Procedure Requirements 9.1 In developing the detailed procedure, the following items should be considered: Instrument manufacturer s operating instructions Scope of materials/objects to be measured Applicability, accuracy requirements Definitions Requirements Personnel Equipment Procedure qualification. 472

81 SE-797 ARTICLE 23 ULTRASONIC STANDARDS SE Procedure Measurement conditions Surface preparation and couplant Calibration and allowable tolerances Scanning parameters Report Procedure used Calibration record Measurement record. type Inspection procedure Type of instrument Calibration blocks, size and material Size, frequency, and type of search unit Scanning method Results Maximum and minimum thickness measurements Location of measurements Personnel data, certification level. 10. Report 10.1 Record the following information at the time of the measurements and include it in the report: 11. Keywords 11.1 contact testing; nondestructive testing; pulseecho; thickness measurement; ultrasonics APPENDIX (Nonmandatory Information) X1. TYPICAL MULTI-STEP THICKNESS GAGE CALIBRATION BLOCKS 473

82 SE SECTION V SE-797 FIG. X1.1 TYPICAL FOUR-STEP THICKNESS CALIBRATION BLOCKS FIG. X1.2 TYPICAL FIVE-STEP THICKNESS CALIBRATION BLOCKS 474