Requirements for bending and flaring of piping Objective, target group and warrant...3 Requirements...3 Cold Bending...4 Induction Bending...

Transcription

1 Technical and professional requirements, TR1969, Final Ver. 2, Valid from Publisher/follow-up: Chiefengineer Materials Technology Classification: Open Validity area: Statoil Group/All locations/all value chains/on- and offshore 1 Objective, target group and warrant Objective Warrant Requirements General Requirements for pipes for cold bending and flaring Cold Bending Wall Thickness Bending of Welded Pipe Limitations and Special Requirements Welding Bending Procedure Qualification Non Destructive Testing in production Production Testing Certification Dimensional Test Induction Bending Wall Thickness Bending of Welded Pipe Post Bending Heat Treatment Bending Procedure Surface conditions Qualification Non Destructive Testing for production Certification Dimensional Test Flaring Design requirements Post flaring heat treatment Flaring Procedure Qualifications Non Destructive Testing for production Production Testing...11

2 5.7 Certification Dimensional Test Definitions Modifications to previous version References...12 App A Limitations and special requirements for cold bent pipes....13

3 1 Objective, target group and warrant 1.1 Objective The purpose of this document is to ensure that cold bending, induction bending and flaring of piping is performed in a consistent manner and meet minimum Company requirements for the products. 1.2 Warrant Project Development (AR05) (Statoil group / All locations / On- and offshore). Operations, maintenance and modifications (AR12) (Statoil group / All locations / On- and offshore). 2 Requirements 2.1 General This document give the requirements for cold bending, induction bending and flaring of piping items designed in accordance with TR2000 (L-SP-200) and ASME B31.3. In case the document is used in connection with other design standards, the conditions and requirements must be agreed with Company. The preferred bending radius for cold bending is 3 x D, however other bending radii may be acceptable. A manufacturing procedure for each site, detailing all requirements, shall be prepared. The following criteria are applicable: All bending and flaring shall be performed in accordance with a written procedure. The procedure shall be qualified when specified. Tubing and small bore piping (Ø < 1 ) may be bent without a qualified procedure. The equipment and process shall be qualified and maintained to ensure that the material properties fulfil the requirements for piping fabrication. The procedures and qualification records shall be available for review. The bending shall as a minimum fulfil the requirements in ASME B31.3 and the requirements of this specification. It is the responsibility of the manufacturer to ensure that all applicable requirements of the Pressure Equipment Directive 97/23/EC are fulfilled, when relevant. 2.2 Requirements for pipes for cold bending and flaring Pipes for cold bending and flaring shall fulfil the requirements in the applicable MDS, ESK and reference standard. Classification: Open Page 3 of 13

4 Titanium pipes, ASTM B861/B862, gr. 2, shall have a minimum elongation of A 5 > 25% (A 4 >27%). Pipes selected for production bending shall have an elongation (stated in the material certificate) which is larger than the sum of the required minimum elongation after bending (10 %) and the reduction in elongation recorded during the qualification. 3 Cold Bending 3.1 Wall Thickness The design pressure of the relevant piping class shall be used for wall thickness calculations. The strength increase of cold bent pipe shall not be included in the pipe wall thickness calculations. Minimum wall thickness at extrados shall be calculated from nominal wall thickness minus the undertolerance. 3.2 Bending of Welded Pipe The longitudinal weld of welded pipes shall be located in a zone ±40 from the bend neutral axis. 3.3 Limitations and Special Requirements The limitations and/or additional testing for the different material types related to cold forming are given in appendix A. The maximum permitted pipe diameter for cold bending is 8. When solution annealing heat treatment is required, the heat treatment manufacturer shall be qualified according to Norsok M-650. This does not apply for heat treatment of 316(L) SS type of materials. 3.4 Welding No welding shall be performed in the plastically deformed zone nor closer than 2 x WT, minimum 30 mm, to this zone unless properly qualified on cold formed material. 3.5 Bending Procedure All cold forming shall be performed in accordance with a written procedure detailing: Material and applicable MDS Diameter Wall thickness after bending (min. / max.) Name and type of forming equipment Relevant forming parameters Inspection and NDT of bends, including acceptance criteria Any post bending heat treatment Production testing Classification: Open Page 4 of 13

5 Maximum fibre elongation and deformation shall be calculated for each procedure. Bending procedures for piping with diameters 1 and larger shall be qualified. 3.6 Qualification The following essential variables shall apply for bend qualification: Material : Each quality and grade / UNS number Type of Pipe : Welded pipe qualifies seamless, but not vice versa Bend Radius : One radius qualifies all larger radii Diameter [D] : + 50% - -50% Wall Thickness [t] : + 25 % % Longitudinal Weld Position Heat Treatment : Any change in PBHT procedure Type of equipment : Any change : One angle from the neutral axis qualifies all lower angles The qualification bend shall be at least 90. Specimens for destructive testing shall be sampled from the area exposed to the most severe deformation. For welded pipe both the weld and base material shall be tested. The material properties of the qualification bend shall be verified by testing after bending. All tests specified in the applicable MDS, ESK and reference standard for pipe and App. A of this document shall be performed. Longitudinal tensile testing shall be performed to verify retained elongation. Acceptance criteria shall be according to the applicable MDS, ESK and reference standard for pipe and appendix A of this document with the following additions: Impact toughness shall satisfy Norsok M-601 table 1. Hardness values shall comply with App. A. The qualification bend shall be subjected to 100 % visual examination and 100 % MT or PT as applicable. For welded pipe the weld area shall be 100 % RT after bending. The use of UT as a substitute for RT may be acceptable for large wall thicknesses. NDT procedures and acceptance criteria shall be according to the reference standards for pipes and fittings as listed in the MDS. The out-of-roundness, wall thickness and other dimensional requirements of the qualification bend shall be checked before and after bending. The requirements of the design code shall be met. Documentation of the qualification shall be: Record of bending method, bending parameters and equipment used. Record of bending radius and angle Report with results of all tests performed. Material certificate 3.7 Non Destructive Testing in production The NDT requirements for cold forming shall be as stated below. The same NDT groups as for M-601 Classification: Open Page 5 of 13

6 are used. For MT and PT the acceptance criteria shall be in accordance with ASME VIII, Div.1, Appendix 6 and 8 respectively. NDT GROUP SERVICE 1 Non-flammable and non-toxic fluids only 2 All systems except those in NDT group 1 PRESSURE RATING STARTING PIPE EXTENT OF NDT [%] 4) Visual MT/PT PN 20 Seamless ) (# 150) Welded 100 2) 3)) 10 PN 20 and 50 Seamless ) (#150 and # 300) Welded All systems PN 100 Welded ) (# 600 and above) Seamless ) Notes: 1) The percentage defines the number of bends of each pipe size, wall thickness and type of material at each fabrication site, which shall be examined 100 %. The bends to be examined shall be uniformly distributed throughout the manufacture and shall be representative for the production. Sub-contractors to the main sites are in this respect considered separate sites. 2) The weld in 10 % of the number of bends of each pipe size, wall thickness and type of material at each fabrication site shall be examined 100 %. Formed area in the base material shall be examined to the same extent as for seamless pipe within the same NDT group. If no defects are found in the weld area in 20 subsequent examined bends per type of material, pipe size and wall thickness, the extent of weld examination may be reduced to 5 % of the number of those bends. The bends to be examined shall be uniformly distributed and shall be representative for the production. Subcontractors to the main sites are in this respect considered separate sites. 3) For 22% Cr and 25% Cr duplex SS bends the weld area in the 3 first produced bends of each pipe size and wall thickness at each fabrication site shall be examined 100 % for each production series where bending parameters have been reset. Provided no defects are revealed during this examination the extent of examination may be reduced to the indicated percentage. Sub-contractors to the main sites are in this respect considered separate sites. 4) If defect indications are revealed, the NDT extent shall be increased to 100 % until the reasons for the defect indications are concluded and necessary corrections in the forming process are made. 2) 3) 3.8 Production Testing All materials, except 22% Cr and 25% Cr Duplex Steel: One set of mechanical production tests shall be carried out for each qualified bending procedure on preferably a pipe with the greatest diameter and wall thickness at the start of the manufacture at each fabrication site. Sub-contractors to the main sites are in this respect considered separate sites. Additional testing may be specified dependant on type of materials, dimensions, quantities to be bent and the results of the qualification testing. 22% Cr and 25% Cr Duplex Steel: Classification: Open Page 6 of 13

7 One set of mechanical production test shall be carried out on each pipe size (OD) and wall thickness at each bending site. Sub-contractors to the main sites are in this respect considered separate sites. The type of tests and acceptance criteria for bends shall be as for qualification. For welded 22% Cr and 25% Cr Duplex SS pipes, material certificates shall be checked; if the lowest reported Charpy V single value is below 100 Joule (standard specimen), impact testing shall be performed for this position after bending to verify compliance with NORSOK M-601. If heat treatment is carried out after bending, testing shall be carried out as specified in the respective MDS, ESK and reference standard. 3.9 Certification Cold bent pipes which have undergone a new heat treatment e.g. normalising, quenched and tempering or solution annealing shall be subject to re-certification. The new testing including lot definition, extent of testing, test location, acceptance criteria, etc. shall be in accordance with the MDS, ESK and reference standard for fittings Dimensional Test All components shall be subject to 100% dimensional check. The dimensions shall comply with the applicable Piping Fabrication Specification, 4 Induction Bending 4.1 Wall Thickness The design pressure of the relevant piping class shall be used for wall thickness calculations. Minimum wall thickness at extrados shall be calculated from nominal wall thickness minus the undertolerance. 4.2 Bending of Welded Pipe The longitudinal weld of welded pipes shall be located in a zone ±40 from the bend neutral axis. 4.3 Post Bending Heat Treatment When solution annealing heat treatment is required, the heat treatment manufacturer shall be qualified according to Norsok M-650. This does not apply for heat treatment of 316(L) SS type of materials. 4.4 Bending Procedure Induction bending shall be performed in accordance with a written and qualified procedure detailing: Material and applicable MDS Classification: Open Page 7 of 13

8 Pipe surface condition Diameter Bend radius Wall thickness after bending (min. / max.) Bending equipment Bending speed Bending temperature Cooling technique Any post bending heat treatment Inspection and NDT of bends, including acceptance criteria 4.5 Surface conditions Pipes selected for induction bending shall be free from rust, dents or surface contaminants which may have a detrimental affect the final product. At no time, prior to or during bending, shall the pipe contact low melting temperature materials such as zinc, aluminium, copper etc. 4.6 Qualification Qualification shall be performed for each combination of the following essential variables: Material : Each quality and grade / UNS number Diameter [D] : +100 % % Wall Thickness [t] : +25 % % Bend Radius : One radius qualifies all larger radii Bending Temperature : ± 25 C, related to position on pipe Bending Speed : ± 20 % Cooling Technique : Any change Post Bending Heat Treatment : Any change Specimens for destructive testing shall be sampled from both intrados and extrados in the bending zone and in the transition zone. For welded pipes, both the base material and the weldment shall be tested. The material properties of the qualification bend shall be verified by testing after bending. The type of test and acceptance criteria shall be as for the applicable MDS and reference standard. For bends intended for sour service the requirements of ISO / NACE MR0175 shall be fulfilled. A sketch for testing shall be made including dimensions and type of test samples. The sketch shall indicate start point of heating and end point of heating The qualification bend shall be subjected to 100 % visual examination and 100 % MT or PT as applicable. For welded pipe the weld area shall be 100 % radiographed after bending. The use of UT as a substitute for RT may be acceptable for large wall thicknesses. NDT procedures and acceptance criteria shall be according to the reference standards for pipes and fittings as listed in the MDS. The out-of-roundness and wall thickness of the qualification bend shall be checked before and after bending. The requirements of the design code shall be met. Classification: Open Page 8 of 13

9 4.7 Non Destructive Testing for production The following NDT shall be performed on all induction bent pipe: Visual Examination : 100 % externally and internally NDT : As given in the relevant MDS, ESK and reference standard for fittings. As a minimum, 2 % of the production bends shall be 100% tested by PT or MT. NDT procedures and acceptance criteria shall be according to the reference standards for pipes and fittings as listed in the MDS. 4.8 Certification All induction bent pipes shall be re-certified. The new testing including lot definition, extent of testing, test location, acceptance criteria, etc. shall be in accordance with the relevant MDS, ESK and the reference standard for fittings. The certificate documenting all specified tests shall be according to EN 10204, type Dimensional Test All components shall be subject to 100% dimensional check. The dimensions shall comply with the applicable Piping Fabrication Specification, 5 Flaring 5.1 Design requirements Production of flared laps at pipe ends can only be performed for pressure rating up to Class 150 when shown on the piping class data sheet, but limited to maximum 8 diameter. For flaring of SS type 316(L), only non-flammable utility services are allowed. All requirements of ASME B31.3 shall be fulfilled. Requirements in paragraph are highlighted: ASME B31.3, para Flared Laps a) The outside diameter of the lap shall be in accordance with dimension of an ASME B16.9 lap-joint stub end.(see deviation below) b) The radius of fillet of the flared lap shall not exceed 3mm, and the backing flange shall meet requirements of para c) The lap thickness, measured at any point, shall be at least 95% of the minimum pipe wall thickness T multiplied by the ratio of the pipe outside radius to the radius at which the lap thickness is measured. d) Pressure design shall be qualified as required by para For qualification of pressure design, burst testing is the preferred method. Classification: Open Page 9 of 13

10 Deviation to ASME B31.3, para Outside diameter of flared lap shall be in accordance with table Post flaring heat treatment When solution annealing heat treatment is required, the heat treatment manufacturer shall be qualified according to Norsok M-650. This does not apply for heat treatment of 316(L) SS type of materials 5.3 Flaring Procedure All flaring shall be performed in accordance with a written and qualified procedure detailing: Material and applicable MDS Diameter Wall thickness Type of forming equipment Relevant forming parameters Inspection and NDT of flared laps including acceptance criteria Any post flaring heat treatment Production testing 5.4 Qualifications Qualification shall be performed for each combination of the following essential variables: Material : Each quality and grade / UNS number Type of Pipe : Welded pipe qualifies seamless, but not vice versa Diameter [D] : + 50 % % Wall Thickness [t] : + 10 % % Outside diameter ratio of : +10% - - No limit flared lap and pipe [D fl /D] Heat Treatment : Any change Type of equipment : Any change The rest ductility shall be checked by tensile testing. Small size tensile test specimens located tangentially as close to the outer edge of the flare as possible shall be used. Minimum elongation shall be 10%. The qualification flare shall be subjected to 100 % visual examination and 100% PT. The acceptance criterion is no cracking. 5.5 Non Destructive Testing for production The NDT requirements for cold forming shall be as stated below. The same NDT groups as for M-601 are used. For PT the acceptance criteria shall be in accordance with ASME VIII, Div.1, Appendix 8. Classification: Open Page 10 of 13

11 NDT GROUP SERVICE 1 Non-flammable and non-toxic fluids only PRESSURE RATING PN 20 (# 150) STARTING PIPE EXTENT OF NDT [%] Visual PT Flared laps 100 Spot 1) Notes: 1) Spot means that 2 % of the number of the flared ends of each pipe size, wall thickness and type of material at each fabrication site shall be examined 100 %. Sub-contractors to the main sites are in this respect considered separate sites. The flared ends to be examined shall be uniformly distributed throughout the manufacturing period and shall be representative of the production. 5.6 Production Testing One production test shall be carried out for each qualified procedure on the largest pipe size and wall thickness to be flared at the start of the manufacture at each fabrication site. Sub-contractors to the main sites are in this respect considered separate sites. Additional testing may be specified dependant on grade of materials, dimensions, quantities to be bent and the results of the qualification testing. Tests and acceptance criteria shall be as specified for qualification testing in sect If heat treatment is carried out of flared laps, testing shall be carried out as specified in the respective MDS and reference standard. 5.7 Certification Flared pipes which have undergone a new heat treatment e.g. normalising, quenched and tempering, or solution annealing shall be subject to re-certification. The new testing including lot definition, extent of testing, test location, acceptance criteria, etc. shall be in accordance with the MDS, ESK and reference standard for fittings. 5.8 Dimensional Test All components shall be subject to 100% dimensional check. The dimensions shall comply with ASME B16.9 lap-joint stub end except outer diameter of flared collar. Table 5-1: Outside diameter of flared lap. Max./Min. dimension on Flared Collar Pipe dim. Max. (mm) Min. (mm) , Classification: Open Page 11 of 13

12 Definitions ESK Element Specification Key HC Hydrocarbon MDS Material Data Sheet MT Magnetic Particle Testing NDT Non Destructive Testing PED Pressure Equipment Directive PBHT Post Bending Heat Treatment PT Penetrant Testing RT Radiographic Testing SS Stainless Steel UT Ultrasonic Testing WT Wall thickness 7 Modifications to previous version Editorial and technical modifications have been performed in several sections of the document. 8 References ASME VIII, Div.1 ASME B31.3 ASME B16.9 ASTM B861/B862 TR2000 (L-SP-200) EN ISO / NACE MR0175 Norsok M-601 Norsok M-650 ASME Boiler and Pressure Vessel Code Process Piping. Factory-Made Wrought Buttwelding Fittings Standard Specification for Titanium and Titanium Alloy Seamless/Welded Pipe. Piping and Valve Material Specification. Metallic products. Types of inspection documents Petroleum and natural gas industries Material for use in H 2 S containing environments in oil and gas production. Welding and Inspection of Piping Qualification of manufacturers for special materials. Classification: Open Page 12 of 13

13 App A Limitations and special requirements for cold bent pipes. MATERIAL 1) MDS SERVICE 2) LIMITATIONS AND/OR ADDITIONAL REQUIREMENTS CMn steel type 235 C01 C02 Utility Service and nonsour HC-service None HC sour service Max. hardness 250 HV10. Post bending heat treatment (PBHT) may be required. CMn-steel for LT service C11 All New heat treatment (normalising or quench and tempering) is required. The material shall be recertified in accordance with the requirements in the applicable MDS and reference standard after heat treatment. The extent of testing, lot definition and acceptance criteria shall be as for the applicable MDS and reference standard for fittings. SS 316 S05 Utility Service and nonsour None HC-service HC sour service Max. hardness 22 HRC. 22 % Cr duplex SS and D22 Utility Service and nonsour HC-service procedure. Test temperature and acceptance criteria shall be as per Norsok M-601 Table 1. Impact testing and hardness of weld and base material shall be included in the qualification of the 25 % Cr duplex SS D35 Solution annealing may be required. The material shall be re-certified in accordance with the requirements in the applicable MDS and reference standard after heat treatment. The extent of testing and lot definition shall be as for the applicable MDS and reference standard for fittings. HC sour service Impact testing and hardness testing of weld and base material shall be included in the qualification of the procedure. The impact test temperature and acceptance criteria shall be as per Norsok M-601, Table 1. Max. hardness shall be 36 HRC for 22% Cr duplex SS with 30<PREN<40 (min. 1.5wt% Mo) and ferrite level 35-65% giving a ph 2 S limit per ISO of 0.02 bar. Max. hardness shall be 36 HRC for 25% Cr duplex SS with 40<PREN<45 and ferrite level 35-65% giving a ph 2 S limit per ISO of 0.2 bar. If the sour service environment is more severe than the limitations given in ISO / NACE MR0175, additional testing is required. Solution annealing may be required. The material shall be re-certified in accordance with the requirements in the applicable MDS, ESK and reference standard after heat treatment. The extent of testing and lot definition shall be as for the applicable MDS, ESK and reference standard for fittings. SS 6Mo S51 All Max. hardness 35 HRC. Titanium Gr. 2 T02 Utility Service and nonsour None. HC-service HC sour service Not accepted. Note 1) Materials which are not listed in this table may be cold bent provided written acceptance from Company is obtained. Note 2) Types 22% Cr and 25% Cr duplex SS in cold worked conditions shall for all services be restricted to a maximum hardness of 32 HRC if used in contact with cathodic protection. Classification: Open Page 13 of 13