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