WPS-2006

Copyright © 2006, TWI LtdWorld Centre for Materials Joining Technology

CSWIP 3.1 Welding InspectionCSWIP 3.1 Welding Inspection

TWI Training & Examination TWI Training & Examination ServicesServices

Welding Procedures Welding Procedures

Course Reference WIS 5Course Reference WIS 5Course notes section reference 5Course notes section reference 5


Welding Procedure QualificationWelding Procedure Qualification

Question:Question:

What is the main reason for carrying out a Welding Procedure What is the main reason for carrying out a Welding Procedure Qualification Test ?Qualification Test ?

(What is the test trying to show ?)(What is the test trying to show ?)

Answer:Answer:

To show that the welded joint has the To show that the welded joint has the propertiesproperties** that satisfy that satisfy the design requirements (fit for purpose)the design requirements (fit for purpose)

* p* propertiesroperties

•mechanical properties are the main interest - mechanical properties are the main interest - always strengthalways strength but but toughness & hardness may be important for some applicationstoughness & hardness may be important for some applications

•test also demonstrates that the weld can be made without defectstest also demonstrates that the weld can be made without defects


Welding Engineer writes a Welding Engineer writes a preliminarypreliminary Welding Procedure Welding Procedure Specification (Specification (ppWPS) for each test weld to be madeWPS) for each test weld to be made

• A welder makes a test weld in accordance with the A welder makes a test weld in accordance with the ppWPSWPS • A welding inspector records all the welding conditions used A welding inspector records all the welding conditions used for the test weld (referred to as the ‘as-run’ conditions)for the test weld (referred to as the ‘as-run’ conditions)

An Independent Examiner/ Examining Body/ Third Party An Independent Examiner/ Examining Body/ Third Party inspector inspector maymay bebe requested to monitor the qualification requested to monitor the qualification processprocess

Welding Procedure QualificationWelding Procedure Qualification(according to EN ISO 15614)(according to EN ISO 15614)

The finished test weld is subjected to NDT in accordance with The finished test weld is subjected to NDT in accordance with the methods specified by the EN ISO Standard - Visual, MT or the methods specified by the EN ISO Standard - Visual, MT or

PT & RT or UTPT & RT or UT



Test weld is subjected to destructive testing (tensile, bend, Test weld is subjected to destructive testing (tensile, bend, macro)macro)The Application Standard, or Client, may require additional The Application Standard, or Client, may require additional tests such as impact tests, hardness tests (and for some tests such as impact tests, hardness tests (and for some materials - corrosion tests)materials - corrosion tests)

(according to EN ISO 15614)(according to EN ISO 15614)

A A Welding Procedure Qualification RecordWelding Procedure Qualification Record ( (WPQRWPQR) is prepared ) is prepared giving details of: -giving details of: -

• The welding conditions used for the test weldThe welding conditions used for the test weld• Results of the NDTResults of the NDT• Results of the destructive testsResults of the destructive tests• The welding conditions that the test weld allows for The welding conditions that the test weld allows for

production weldingproduction weldingThe The Third PartyThird Party may be requested to sign the WPQR as a true may be requested to sign the WPQR as a true recordrecord


The welding engineer writes The welding engineer writes qualified qualified Welding Procedure Welding Procedure Specifications (WPS) for production weldingSpecifications (WPS) for production welding

Welding Procedure Qualification Welding Procedure Qualification

Production Production welding conditionswelding conditions must remain within the must remain within the range of range of qualificationqualification allowed by the allowed by the WPQRWPQR

(according to EN ISO 15614)(according to EN ISO 15614)


Welding Procedure QualificationWelding Procedure Qualification(according to EN Standards)(according to EN Standards)

welding conditionswelding conditions are called are called welding variableswelding variables

welding variables are classified by the EN ISO Standard as:welding variables are classified by the EN ISO Standard as:

•Essential variablesEssential variables

•Non-essential variablesNon-essential variables

•Additional variablesAdditional variables

Note:Note: additional variables = ASME supplementary essential additional variables = ASME supplementary essential

The The range of qualificationrange of qualification for production welding is based on for production welding is based on the limits that the EN ISO Standard specifies for the limits that the EN ISO Standard specifies for essential essential variables*variables*

((** and when applicable - the additional variables) and when applicable - the additional variables)



WELDING ESSENCIALWELDING ESSENCIAL VARIABLESVARIABLES

Question: Question:

Why are some welding variables classified as Why are some welding variables classified as essential essential ??

Answer:Answer:

A variable, that if changed beyond certain limits (specified by A variable, that if changed beyond certain limits (specified by the Welding Standard) may have the Welding Standard) may have a significant effecta significant effect on the on the propertiesproperties* of the joint* of the joint

* particularly joint strength and ductility* particularly joint strength and ductility



WELDING ADDITIONAL VARIABLESWELDING ADDITIONAL VARIABLES

Question: Question:

Why are some welding variables classified as Why are some welding variables classified as additionaladditional ??

Answer: Answer:

A variable, that if changed beyond certain limits (specified by A variable, that if changed beyond certain limits (specified by the Welding Standard) may have the Welding Standard) may have a significant effecta significant effect on the on the toughnesstoughness and/or and/or hardnesshardness of the joint of the joint

NoteNote: : ASME calls variables that affect toughness as supplementary ASME calls variables that affect toughness as supplementary essential variables (but does not refer to hardness)essential variables (but does not refer to hardness)



(according to EN Standards)(according to EN Standards)

SOME TYPICAL SOME TYPICAL ESSENTIALESSENTIAL VARIABLES VARIABLES

• Welding ProcessWelding Process

• Post Weld Heat Treatment (PWHT)Post Weld Heat Treatment (PWHT)

• Material TypeMaterial Type

• Electrode Type, Filler Wire Type (Classification)Electrode Type, Filler Wire Type (Classification)

• Material ThicknessMaterial Thickness

• Polarity (AC, DC+ve / DC-ve)Polarity (AC, DC+ve / DC-ve)

• Pre-Heat TemperaturePre-Heat Temperature

SOME TYPICAL SOME TYPICAL ADDITIONALADDITIONAL VARIABLES VARIABLES

• Heat InputHeat Input

• Welding PositionWelding Position


Welding ProceduresWelding ProceduresProducing a welding procedure involves: Producing a welding procedure involves:

• Planning the tasksPlanning the tasks

• Collecting the dataCollecting the data

• Writing a procedure for use of for trialWriting a procedure for use of for trial

• Making a test weldsMaking a test welds

• Evaluating the resultsEvaluating the results

• Approving the procedureApproving the procedure

• Preparing the documentationPreparing the documentation


Welding ProceduresWelding ProceduresComponents of a welding procedureComponents of a welding procedure

Parent materialParent material• Type (Grouping)Type (Grouping)• ThicknessThickness• Diameter (Pipes)Diameter (Pipes)• Surface condition)Surface condition)

Welding processWelding process• Type of process (MMA, MAG, TIG, SAW etc)Type of process (MMA, MAG, TIG, SAW etc)• Equipment parametersEquipment parameters• Amps, Volts, Travel speedAmps, Volts, Travel speed

Welding ConsumablesWelding Consumables• Type of consumable/diameter of consumableType of consumable/diameter of consumable• Brand/classificationBrand/classification• Heat treatments/ storageHeat treatments/ storage


Welding ProceduresWelding ProceduresComponents of a welding procedure Components of a welding procedure

Joint designJoint design•Edge preparationEdge preparation•Root gap, root faceRoot gap, root face•Jigging and tackingJigging and tacking•Type of bakingType of baking

Welding PositionWelding Position•Location, shop or siteLocation, shop or site•Welding position e.g. 1G, 2G, 3G etcWelding position e.g. 1G, 2G, 3G etc•Any weather precautionAny weather precaution

Thermal heat treatmentsThermal heat treatments•Preheat, tempsPreheat, temps•Post weld heat treatments e.g. stress relieving Post weld heat treatments e.g. stress relieving


Object of a welding procedure testObject of a welding procedure test

To give maximum confidence that the welds mechanical To give maximum confidence that the welds mechanical and metallurgical properties meet the requirements of the and metallurgical properties meet the requirements of the applicable code/specification.applicable code/specification.

Each welding procedure will show a range to which the Each welding procedure will show a range to which the procedure is approved (extent of approval)procedure is approved (extent of approval)

If a customer queries the approval evidence can be If a customer queries the approval evidence can be supplied to prove its validitysupplied to prove its validity

Welding ProceduresWelding Procedures


Welding ProceduresWelding ProceduresApproving the procedure:Approving the procedure:• When the data has been collected, the procedure must be When the data has been collected, the procedure must be

validated by producing a test weld,validated by producing a test weld, weld procedure test weld procedure test (WPT)(WPT)..

• A number of standards provides information with regards A number of standards provides information with regards to approving a procedure, but normally this will require the to approving a procedure, but normally this will require the WPT to be tested by NDT and mechanical testing.WPT to be tested by NDT and mechanical testing.

• The locations and tests required will be given in the The locations and tests required will be given in the applicable code or standardapplicable code or standard

• Most codes and standards provide a report format to Most codes and standards provide a report format to record the resultsrecord the results


After the testing is completed and all the relevant results After the testing is completed and all the relevant results collated, the results need to be assessed in accordance with collated, the results need to be assessed in accordance with the relevant code/standard. The results are then generally the relevant code/standard. The results are then generally recorded.recorded.

Once the welding procedure has been approved, If any Once the welding procedure has been approved, If any essential variableessential variable is changed during production the WPS may is changed during production the WPS may require re-approval. require re-approval.

Most codes/procedures dealing with procedure qualifications Most codes/procedures dealing with procedure qualifications provide a list of what is an provide a list of what is an essential essential or or non-essential variablenon-essential variable



Summary of designations:Summary of designations:

pWPS:pWPS: Preliminary Welding Procedure Specification Preliminary Welding Procedure Specification

(Before procedure approval)(Before procedure approval)

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

(Welding procedure Qualification record)(Welding procedure Qualification record)

WPS:WPS: Welding Procedure Specification Welding Procedure Specification

(After procedure approval)(After procedure approval)



Example: Example:

Welding Welding

Procedure Procedure

Specification Specification

(WPS)(WPS)


Welding ProceduresWelding ProceduresPURPOSE OF A WPSPURPOSE OF A WPS

TO ACHIEVE SPECIFIC PROPERTIESTO ACHIEVE SPECIFIC PROPERTIES

mechanical strength, corrosion resistance, compositionmechanical strength, corrosion resistance, composition

TO ENSURE FREEDOM FROM DEFECTSTO ENSURE FREEDOM FROM DEFECTS

TO ENFORCE QC PROCEDURESTO ENFORCE QC PROCEDURES

TO STANDARDISE ON METHODS AND COSTSTO STANDARDISE ON METHODS AND COSTS

TO CONTROL PRODUCTION SCHEDULESTO CONTROL PRODUCTION SCHEDULES

TO FORM A RECORDTO FORM A RECORD

APPLICATION STANDARD OR CONTRACT REQUIREMENTAPPLICATION STANDARD OR CONTRACT REQUIREMENT


CSWIP 3.1 Welding InspectionCSWIP 3.1 Welding Inspection

TWI Training & Examination TWI Training & Examination ServicesServices

Welder ApprovalWelder ApprovalExample BS EN 287Example BS EN 287

Course Reference WIS 5Course Reference WIS 5Course notes section reference 5Course notes section reference 5


Welder QualificationWelder Qualification(according to EN Standards)(according to EN Standards)

Question:Question:

What is the main reason for qualifying a welder ?What is the main reason for qualifying a welder ?

Answer:Answer:

To show that he has the skill to be able to make production To show that he has the skill to be able to make production welds that are free from defectswelds that are free from defects

Note:Note: when welding in accordance with a Qualified WPS when welding in accordance with a Qualified WPS


Welder QualificationWelder Qualification(according to EN 287 )(according to EN 287 )

An approved WPS should be available covering the range of An approved WPS should be available covering the range of qualification required for the welder approval.qualification required for the welder approval.

• The welder qualifies in accordance with an approved WPSThe welder qualifies in accordance with an approved WPS • A welding inspector monitors the welding to make sure that A welding inspector monitors the welding to make sure that the welder uses the conditions specified by the WPSthe welder uses the conditions specified by the WPS

EN Welding Standard states that an Independent Examiner, EN Welding Standard states that an Independent Examiner, Examining Body or Third Party Inspector Examining Body or Third Party Inspector maymay bebe required to required to monitor the qualification processmonitor the qualification process


The finished test weld is subjected to NDT by the methods The finished test weld is subjected to NDT by the methods specified by the EN Standard - Visual, MT or PT & RT or UTspecified by the EN Standard - Visual, MT or PT & RT or UT

The test weld may need to be destructively tested - for certain materials and/or welding processes specified by the EN Standard or the Client Specification


• A Welder’s Qualification Certificate is prepared showing the A Welder’s Qualification Certificate is prepared showing the conditions used for the test weld and the range of qualification conditions used for the test weld and the range of qualification allowed by the EN Standard for production weldingallowed by the EN Standard for production welding

• The Qualification Certificate is usually endorsed by a Third The Qualification Certificate is usually endorsed by a Third Party Inspector as a true record of the testParty Inspector as a true record of the test


The welder is allowed to make production welds within the The welder is allowed to make production welds within the range of qualification shown on the Certificaterange of qualification shown on the Certificate

The The range of qualification allowed for production welding is range of qualification allowed for production welding is based on the limits that the EN Standard specifies for the based on the limits that the EN Standard specifies for the welder qualification essential variableswelder qualification essential variables


A Welder’s Qualification Certificate automatically expires if the A Welder’s Qualification Certificate automatically expires if the welder has not used the welding process for 6 months or welder has not used the welding process for 6 months or longerlonger

A Certificate may be withdrawn by the Employer if there is A Certificate may be withdrawn by the Employer if there is reason to doubt the ability of the welder, for examplereason to doubt the ability of the welder, for example

• a high repair ratea high repair rate• not working in accordance with a qualified WPSnot working in accordance with a qualified WPS


ESSENTIAL VARIABLESESSENTIAL VARIABLES

Question:Question:

What is a ‘welder qualification essential variable’ ?What is a ‘welder qualification essential variable’ ?

(what makes the variable ‘essential’ ? )(what makes the variable ‘essential’ ? )

Answer:Answer:

A variable, that if changed beyond the limits specified by the A variable, that if changed beyond the limits specified by the EN Standard, may require more skill than has been EN Standard, may require more skill than has been demonstrated by the test welddemonstrated by the test weld



Typical Welder Essential VariablesTypical Welder Essential Variables

• Welding ProcessWelding Process

• Material Type Material Type

• Electrode TypeElectrode Type

• Material ThicknessMaterial Thickness

• Pipe DiameterPipe Diameter

• Welding PositionWelding Position

• Weld Backing Weld Backing (an unbacked weld requires more skill)(an unbacked weld requires more skill)



Numerous codes and standards deal with welder qualification, Numerous codes and standards deal with welder qualification, e.g. BS EN 287.e.g. BS EN 287.

• Once the content of the procedure is approved the next Once the content of the procedure is approved the next stage is to approve the welders to the approved procedure. stage is to approve the welders to the approved procedure.

• A welders test know as a A welders test know as a Welders Qualification Test (WQT).Welders Qualification Test (WQT).

Object of a welding qualification test:Object of a welding qualification test:

• To give maximum confidence that the welder meets the To give maximum confidence that the welder meets the quality requirements of the approved procedure (WPS).quality requirements of the approved procedure (WPS).

• The test weld should be carried out on the same material and The test weld should be carried out on the same material and same conditions as for the production welds.same conditions as for the production welds.

Welder QualificationWelder Qualification


Information that should be included on a welders Information that should be included on a welders test certificate are:test certificate are:

• Welders name and identification number• Date of test and expiry date of certificate• Standard/code e.g. BS EN 287• Test piece details• Welding process.• Welding parameters, amps, volts• Consumables, flux type and filler classification details• Sketch of run sequence • Welding positions• Joint configuration details• Material type qualified, pipe diameter etc• Test results, remarks• Test location and witnessed by• Extent (range) of approval

Welder QualificationWelder Qualification


Example: Example:

Welder Welder

Approval Approval

Qualification Qualification

CertificationCertification


Welding PositionsWelding Positions

PAPA 1G / 1F1G / 1F Flat / DownhandFlat / Downhand

PBPB 2F2F Horizontal-VerticalHorizontal-Vertical

PCPC 2G2G HorizontalHorizontal

PDPD 4F4F Horizontal-Vertical (Overhead)Horizontal-Vertical (Overhead)

PEPE 4G4G OverheadOverhead

PFPF 3G / 5G3G / 5G Vertical-UpVertical-Up

PGPG 3G / 5G3G / 5G Vertical-DownVertical-Down

H-L045H-L045 6G6G Inclined Pipe (Upwards)Inclined Pipe (Upwards)

J-L045J-L045 6G6G Inclined Pipe (Downwards)Inclined Pipe (Downwards)


Welding PositionsWelding Positions

ISO


PA / 1GPA / 1GPA / 1FPA / 1F

PC / 2GPC / 2GPB / 2FPB / 2F

PD / 4FPD / 4FPE / 4GPE / 4G PG / 3GPG / 3G

PF / 3GPF / 3G

Plate/ Fillet Weld PositionsPlate/ Fillet Weld Positions


Pipe Welding PositionsPipe Welding Positions

Weld: FlatWeld: FlatPipe: rotatedPipe: rotatedAxis: Horizontal Axis: Horizontal

PA / 1GPA / 1G

Weld: Vertical DownwardsWeld: Vertical DownwardsPipe: FixedPipe: FixedAxis: Horizontal Axis: Horizontal

PG / 5G PG / 5G

Weld: Vertical upwardsWeld: Vertical upwardsPipe: FixedPipe: FixedAxis: Horizontal Axis: Horizontal

PF / 5G PF / 5G

Weld: Upwards Weld: Upwards Pipe: FixedPipe: FixedAxis: Inclined Axis: Inclined

Weld: HorizontalWeld: HorizontalPipe: FixedPipe: FixedAxis: Vertical Axis: Vertical

PC / 2G PC / 2G

4545oo

Weld: Downwards Weld: Downwards Pipe: FixedPipe: FixedAxis: Inclined Axis: Inclined

J-LO 45 / 6GJ-LO 45 / 6G

4545oo

H-LO 45 / 6GH-LO 45 / 6G


Any QuestionsAny Questions

??

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