Welding Procedure Specification

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CSWIP Welder Training Weld Procedures Copyright © 2003 TWI Ltd

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Welding Procedures (BS EN 288)

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Welding Procedures Producing a welding procedure involves:  Planning the tasks  Collecting the data  Writing a procedure for use of for trial  Making a test welds  Evaluating the results  Approving the procedure  Preparing the documentation Copyright © 2003 TWI Ltd

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Welding Procedures In most codes reference is made to how the procedure are to be devised and whether approval of these procedures is required. The approach used for procedure approval depends on the code: Example codes:

 AWS D.1.1: Structural Steel Welding Code  BS 2633: Class 1 welding of Steel Pipe Work  API 1104: Welding of Pipelines  BS 4515: Welding of Pipelines over 7 Bar Other codes may not specifically deal with the requirement of a procedure but may contain information that may be used in writing a weld procedure  EN 1011Process of Arc Welding Steels Copyright © 2003 TWI Ltd

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Welding Procedures Components of a welding procedure Parent material • Type (Grouping) • Thickness • Diameter (Pipes) • Surface condition)  Welding process • Type of process (MMA, MAG, TIG, SAW etc) • Equipment parameters • Amps, Volts, Travel speed  Welding process • Type of process (MMA, MAG, TIG, SAW etc) • Equipment parameters • Amps, Volts, Travel speed  Welding Consumables • Type of consumable/diameter of consumable • Brand/classification • Heat treatments/ storage

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Welding Procedures  Joint design • Edge preparation • Root gap, root face • Jigging and tacking • Type of baking  Welding Position • Location, shop or site • Welding position e.g. 1G, 2G, 3G etc • Any weather precaution  Welding Variables • Run sequences • Back gouging • Interpass temperatures  Thermal heat treatments • Preheat, temps • Post weld heat treatments e.g. stress relieving Copyright © 2003 TWI Ltd

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Welding Procedures Approving the procedure:  When the data has been collected, the procedure must be validated by producing a test weld, weld procedure test (WPT).  A number of standards provides information with regards to approving a procedure, but normally this will require the WPT to be tested by NDT and mechanical testing.  The locations and tests required will be given in the applicable code or standard  Most codes and standards provide a report format to record the results Copyright © 2003 TWI Ltd

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Welding Procedures Examination and testing requirements of a WPT for procedure approval (BS EN 288)

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Welding Procedures After the testing is completed and all the relevant results collated, the results need to be assessed in accordance with the relevant code/standard. The results are then generally recorded.  pWPS: Preliminary Welding Procedure Specification Before procedure approval.  WPS: Welding Procedure Specification After procedure approval  WPAR (WPQR): Welding Procedure Approval Record Welding procedure test record

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Welding Procedures Once the welding procedure has been approved, If any essential variable is changed during production the WPS may require re-approval. Most codes/procedures dealing with procedure qualifications provide a list of what is an essential or non-essential variable. Object of a welding procedure test To give maximum confidence that the welds mechanical and metallurgical properties meet the requirements of the applicable code/specification. Each welding procedure will show a range to which the procedure is approved (extent of approval) If a customer queries the approval evidence can be supplied to prove its validity Copyright © 2003 TWI Ltd

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Example: Welding Procedure Specification (WPS)

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Welder Approvals (BS EN 287)

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Welder Approval Numerous codes and standards deal with welder qualification, e.g. BS EN 287. Once the content of the procedure is approved the next stage is to approve the welders to the approved procedure. A welders test know as a Welders Qualification Test (WQT). Object of a welding qualification test . To give maximum confidence that the welder meets the requirements of the approved procedure (WPS).  The test weld should be carried out on the same material and same conditions as for the site welds  The welder who carries out the procedure qualification weld automatically qualify when the procedure qualifies Copyright © 2003 TWI Ltd

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Welder Approval Information that should be included on a welders test certificate are: 1. Welders name and identification number 2. Date of test and expiry date of certificate 3. Standard/code e.g. BS EN 287 4. Test piece details 5. Welding process, welding parameters, amps, volts 6. Welding parameters, amps, volts 7. Consumables, flux type and filler classification details 8. Sketch of run sequence, welding positions 9. Joint configuration details 10. Material type qualified, pipe diameter etc 11. Test results, remarks 12. Test location and witnessed by 13. Extent (range) of approval Copyright © 2003 TWI Ltd

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Range of approval according to electrode flux type

BS EN 287 Range of approval according material groups

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Welder Approval The inspection of a welders qualification test.  It is normal for a qualified inspectors usually from an independent body to witness the welding.  Under normal circumstances only one test weld per welder is permitted  If the welder fails the test weld and the failure is not the fault of the welder e.g. faulty welding equipment then a re-test would be permitted.  The testing of the test weld is done in accordance with the applicable code, but it is not normal to carry out test that test for the mechanical properties of welds e.g. tensile, charpy and hardness tests. Copyright © 2003 TWI Ltd

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Welder Approval Tests methods required for welder qualification (BS EN 287)

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Example: Welder Approval Qualification Certification

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Any Any Questions? Questions?

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Questions QU 1. State six essential variables in a welding procedure. QU 2. What do you understand by the term extent of approval and give four examples. QU 3. Describe what you understand by a welding procedure specification, A welding procedure approval record and a welder certificate QU 4. What is the reason for approving a welding procedure and a welder QU 5. Give three reasons why a welder may require requalification. Copyright © 2003 TWI Ltd

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