Specification for DSAW Pipe

Transcription

1 Specification for DSAW Pipe Specification for DSAW Pipe 1 of 8

2 Table of Contents 1.0 INTRODUCTION Specification for DSAW Pipe 2 of 8

3 1.0 INTRODUCTION The purpose of this Data Sheet is to define the additional requirements that must be considered when procuring Carbon Manganese seamless linepipe in accordance with requirements of API 5L : 95 (Forty first edition). Where conflict between the requirements herein and the requirements of API 5L exist then the requirements herein shall take precedence. The clause references hereunder are those referred to in API 5L: 1.1 Clause 6.0 Material Requirement (MPQ s) For each pipe diameter and wall thickness a material procedure qualification trial (MPQ) shall be carried out. From the first day production 10 pipe joints shall be selected by CSO where 1 pipe joint shall be evaluated by all mechanical tests and inspections required by this specification. Where production is to be split in to more than one phase CSO reserves the right to request all production testing to be repeated. 1.2 Clause 6.0 Material Requirement (MPQ s) As part of the MPQ s a set of three charpy specimens shall be tested from weld metal, pipe body and HAZ at the following test temperatures from one of the test rings to establish transition curves, 20 C, 0 C, 20 C, 40 C, 60 C and 80 C. 1.3 Clause 6.0 Material Requirement (MPQ s) As part of the MPQ s a three sets of charpy specimens sample shall be subjected to 5% longitudinal strain and then aged at a temperature of 250 C for 1 hour and then tested in accordance with requirements of this specification. These specimens shall be pipe body (longitudinal), WCL, WFL and WFL+2mm. 1.4 Clause 6.0 Material Requirement (MPQ s) As part of the MPQ s the following test for surface condition shall be carried out on the first ten pipes from the first days production: a) Preheat pipe surface to 70 C b) Grit blast each pipe to SA 2.5 c) Heat to 240 C and cool in air Each pipe shall then be visually inspected, the surface condition of the pipes shall be such that upon production coating of a thin film system the level of surface defects encountered would not cause a time delay during the coating operation. The total number of defects should able to be removed in no longer than 3 man minutes per pipe. Specification for DSAW Pipe 3 of 8

4 1.5 Clause 6.0 Material Requirement (MPQ s) Where pipeline service is defined as sour test coupons for step wise cracking test shall be cut. After exposure to the test, in accordance with NACE TM 02 84, using a test solution in accordance with TM 01 77, coupons shall be examined by ultrasonic testing to an approved procedure prior to sectioning. The reference reflector shall be a 2mm flat bottomed hole at mid thickness, and the area of any cracking exceeding this level shall not be more than 5% of the total surface area of the coupon. If no cracking is detected by this technique sectioning shall not be required. If the reflection area is between zero and 5%, sections shall be taken through the strongest reflectors; the CSR value shall not exceed 2%. 1.6 Clause 6.0 Material Requirement (MPQ s) When defined in the ITT documentation, Three samples shall be subjected to a SSC test in accordance with NACE standard TM and the following additions, the samples shall be taken from the pipe selected for the MPQ s. Each sample shall be 115mm long x 15mm wide x 5mm thick and shall contain a section of the longitudinal weld at it s centre, samples shall be machined from the bore of the pipe and then flattened. The test solution shall be synthetic seawater saturated with H2S to a level of ppm to a give a ph of in accordance with NACE TM The test temperature shall be 24 C +/ 3 C and the test duration shall be 720Hrs, stress application shall be by 4 point bending to a level of 0.72 x SMYS. On completion of testing the samples shall be scrubbed clean in water, dried and sprayed with a PVC lacquer. The edges shall be polished metallographically to a minimum of 800 grit and inspected both by eye and at a magnification of X100. Only cracks in the through thickness direction shall be evaluated. No cracking shall occur within the test duration of 720Hrs which exceeds 0.1mm in the through thickness direction. 1.7 Clause Chemical Composition Manufacturer shall submit proposed aim chemistry and range for the product and the ladle analysis at tender submission for review, 1.8 Clause Tensile Tests The maximum yield strength and UTS shall not exceed the specified minimum values by more than 100N/mm 2 and the yield strength to tensile strength ratio shall not exceed A stress/strain curve for each test shall be retained and submitted as part of the as built documentation. A cross weld tensile specimen, in accordance with BS709, Specification for DSAW Pipe 4 of 8

5 shall be taken from each test ring and the transverse tensile specimen shall be taken at 180 from the weld location. At all times the weld all weld metal tensile strength shall overmatch the actual production pipe material strength 1.9 Clause Charpy Tests For SAW pipe material charpy specimens from the weld area shall be taken from the WCL, WFL & WFL+2mm locations, parent material shall be located at 90 from the weld. The acceptance criteria for charpy testing shall be as detailed below, the test temperature for charpy tests shall be 20 C Minimum Average Minimum Individual Parent Material Weld /HAZ 80 Joules 80 Joules 60 Joules 60 Joules 1.10 Clause Hardness Tests Additional Clause: Two macro sections shall be taken be prepared from one of the two test rings and hardness tested, one macro shall be for parent material and the other shall be for the weld seam. The parent material hardness survey shall consist of a complete traverse should be made across the complete thickness of the material with indentations spaced at 2mm to include indentations at both the internal and external surfaces, the survey shall be commenced and completed 1.5mm from the specimens edges, using a 10Kg load in accordance with BS 427: part 1, the weld seam survey shall be carried out in accordance with figure 4 of this specification. The maximum allowable hardnesses shall not exceed those given below. Pipe Location Max Hardness (Hv10) Non Sour Service Sour Service Pipe Body Weld Metal /HAZ Clause 7.2 Pipe End I.D. Tolerance The inside diameter of the pipe end (for a distance of 100mm from the bevel) shall be checked at both ends by a rod gauge or similar type instrument to be approved by CSO. The results of these Specification for DSAW Pipe 5 of 8

6 checks shall be recorded for a frequency of 1 in 20 where the deviation from the nominal pipe I.D. shall be no more than +/ 2.0mm where measurements are taken in 2 planes at 90 to each other (the nominal I.D. shall be defined as the pipe O.D. minus 2 x the specified nominal wall thickness) Clause 7.3 Wall Thickness The wall thickness measured at any point shall not vary from the specified nominal thickness by more than 8, +15%. The wall thickness shall be determined by ultrasonic testing Length The pipe joint shall be supplied in lengths of 12.0m 0.1m, +0.5m Jointers Jointers shall not be permitted Clause 7.8 Repair Of Weld Defects. A maximum of three repairs per pipe shall be permitted upto a maximum of 5% of the pipe length, no re repairs shall be permitted SAW Weld Bead Height and Profile The angle of weld bead re inforcemnet shall be such it is suitable for application of all coating systems without tenting occurring between the weld toe and the inner surface of the coating system. The maximum permissible bead height shall be 3mm Other Defects All pipe pitting in excess of 1.5mm depth shall be subject to remedial work. All pipe ends shall be cleaned free of excessive grease, oil and manufacturing debris Testing of Mechanical Properties Production testing shall be carried out at a frequency of one set of tests per 50 pipes with a minimum of one set per heat. No weld repairs shall be carried out on the pipe after the cold sizing operation or on the pipe body. No weld repairs shall be carried out in the last 200mm of the pipe ends but shall have the affected length of pipe cut off. Pipe with cracks to the body or the weld area shall be rejected Clause Fracture Toughness Testing Additional Clause: Charpy testing shall be carried out on each production test pipe selected in accordance with API 5L appendix SR5, the acceptance criteria shall be as Specification for DSAW Pipe 6 of 8

7 detailed in section of this specification Clause Hydrostatic Testing The hold duration for the hydrostatic test shall be not less than 10 seconds Clause Hydrostatic Test pressure The test pressure shall result in a hoop stress (based on a specified minimum wall thickness) equal to 95% of the SMYS Clause 9.6 Visual Inspection Addition : All pipe material shall have an external surface condition such that upon blasting to a finish of Sa 2.5 by the coating contractor a profile of Ra <20 and Rt < 100 is achieved, all pipe internal surface shall be free of millscale and rust Clause 9.6 Residual Magnetism Additional Clause: The residual magnetism in finished pipes shall be checked by measurement of the magnetic flux density at a location immediately adjacent to the pipe ends using a suitable probe or gauss meter approved by CSO. Checks shall be carried out on 3 pipes per shift in the as supplied condition with the maximum permissible level of magnetism being 20 Gauss. CONTRACTOR shall be responsible for ensuring that this maximum level is not exceeded in the as delivered condition (ie. CSO nominated spoolbase, installation vessel or storage yard) Clause 9.7 Non Destructive Examination All NDE shall be performed on completion of heat treatment and hydrostatic testing Clause 9.7 Non Destructive Examination All operators shall be qualified to SNT TC 1A or equivalent, operators shall be qualified to level 1 or 2 with supervisors qualified to level Clause 9.7 Non Destructive Examination Each pipe length shall be examined in accordance with API 5L SR4, the pipe body shall be examined 100% for laminations by ultrasonics and the completed bevels shall be inspected for laminations and cracks by 100% MPI and manual Ultrasonics over a width of 100mm from the bevel at each end Clause Repair of Defects Repair of defects by welding shall not be permitted. Specification for DSAW Pipe 7 of 8

8 1.28 Clause 10 A coloured paint band, minimum 50mm wide shall be applied on the internal surface of each pipe 100mm from the end. The colour system employed shall be such that pipes of similar diameters, but differing wall thicknesses, are readily identifiable Appendix D Weldability Trial Delete clause and replace with following: The manufacturer shall supply weldability data for a product which is reflective of the project linepipe in terms of grade, dimensions, process route, chemical composition and heat treatment. Should this data be unacceptable to CSO the manufacturer shall carry out weldability trials under the instruction of CSO at the manufacturers cost Appendix D Reelability Data Additional Clause The manufacturer shall supply reelability data for a product which is reflective of the project linepipe in terms of grade, dimensions, process route, chemical composition and heat treatment. Should this data be unavailable or unacceptable to CSO the manufacturer shall carry out reelability trials under the instruction of CSO at the manufacturers cost. Specification for DSAW Pipe 8 of 8