welding procedure specification

M.S.RogersM.S.Rogers

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Copyright © 2003 TWI Ltd

CSWIP Welder TrainingWeld Procedures


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Welding ProceduresWelding Procedures(BS EN 288)(BS EN 288)


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Welding ProceduresWelding ProceduresProducing 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


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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

Welding ProceduresWelding Procedures


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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

Components of a welding procedureComponents of a welding procedure


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Welding ProceduresWelding 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


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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

Approving the procedure:Approving the procedure:


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Welding ProceduresWelding ProceduresExamination and testing requirements of a WPT for procedure approval (BS EN 288)


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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:pWPS: Preliminary Welding Procedure Specification

Before procedure approval.

WPSWPS:: Welding Procedure Specification

After procedure approval

WPAR (WPQR):WPAR (WPQR): Welding Procedure Approval Record

Welding procedure test record


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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 testObject 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


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Example: Example:

Welding Procedure Welding Procedure

Specification (WPS)Specification (WPS)


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Welder ApprovalsWelder Approvals(BS EN 287)(BS EN 287)


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Welder ApprovalWelder 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 testObject 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 weldsThe welder who carries out the procedure qualification weld

automatically qualify when the procedure qualifies


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Welder ApprovalWelder ApprovalInformation that should be included on a welders test certificate are:1. Welders name and identification number2. Date of test and expiry date of certificate3. Standard/code e.g. BS EN 2874. Test piece details5. Welding process, welding parameters, amps, volts6. Welding parameters, amps, volts7. Consumables, flux type and filler classification details8. Sketch of run sequence, welding positions9. Joint configuration details10.Material type qualified, pipe diameter etc11.Test results, remarks12.Test location and witnessed by13.Extent (range) of approval


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Range of approval according to electrode flux type

Range of approval according material groups

BS EN 287


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Welder ApprovalWelder ApprovalThe 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.


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Welder ApprovalWelder Approval

Tests methods required for welder qualification(BS EN 287)


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Example: Example:

Welder Approval Welder Approval

Qualification Qualification

CertificationCertification


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Any Questions?Any Questions?


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QU 1. State six essential variables in a welding procedure.

QuestionsQuestions

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 re-qualification.

welding procedure specification

Documents

give maximum confidence

equipment parameters amps

welding procedure specification

welders qualification test

welding parameters

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