wps welder qualifications section 5

Welding Inspector

WPS – Welder Qualifications

Section 5

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Welding Procedure Qualification 5.1

Question:

What is the main reason for carrying out a Welding Procedure

Qualification Test ?

(What is the test trying to show ?)

Answer:

To show that the welded joint has the properties* that satisfy

the design requirements (fit for purpose)

* properties

•mechanical properties are the main interest - always strength but

toughness & hardness may be important for some applications

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

Welding Procedures 5.1

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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


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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

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The welding engineer writes qualified Welding Procedure

Specifications (WPS) for production welding


Production welding conditions must remain within the range of

qualification allowed by the WPQR

(according to EN ISO 15614)

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(according to EN Standards)

welding conditions are called welding variables

welding variables are classified by the EN ISO Standard as:

•Essential variables

•Non-essential variables

•Additional variables

Note: additional variables = ASME supplementary essential

The range of qualification for production welding is based on

the limits that the EN ISO Standard specifies for essential

variables*

(* and when applicable - the additional variables)

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WELDING ESSENTIAL VARIABLES

Question:

Why are some welding variables classified as essential ?

Answer:

A variable, that if changed beyond certain limits (specified by

the Welding Standard) may have a significant effect on the

properties* of the joint

* particularly joint strength and ductility

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SOME TYPICAL ESSENTIAL VARIABLES

• Welding Process

• Post Weld Heat Treatment (PWHT)

• Material Type

• Electrode Type, Filler Wire Type (Classification)

• Material Thickness

• Polarity (AC, DC+ve / DC-ve)

• Pre-Heat Temperature

• Heat Input

• Welding Position


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 Consumables• Type of consumable/diameter of consumable

• Brand/classification

• Heat treatments/ storage

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Components of a welding procedure

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

Thermal heat treatments•Preheat, temps

•Post weld heat treatments e.g. stress relieving

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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

Welding Procedures

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Summary of designations:

pWPS: Preliminary Welding Procedure Specification

(Before procedure approval)

WPAR (WPQR): Welding Procedure Approval Record

(Welding procedure Qualification record)

WPS: Welding Procedure Specification

(After procedure approval)

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Example:

Welding

Procedure

Specification

(WPS)

Welder Qualification 5.4

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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

quality requirements of the approved procedure (WPS).

• The test weld should be carried out on the same material and

same conditions as for the production welds.

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Welder Qualification 5.4 & 5.5


Question:

What is the main reason for qualifying a welder ?

Answer:

To show that he has the skill to be able to make production

welds that are free from defects

Note: when welding in accordance with a Qualified WPS

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The welder is allowed to make production welds within the

range of qualification shown on the Certificate

The range of qualification allowed for production welding is

based on the limits that the EN Standard specifies for the

welder qualification essential variables


(according to EN 287 )

A Certificate may be withdrawn by the Employer if there is

reason to doubt the ability of the welder, for example

• a high repair rate

• not working in accordance with a qualified WPS

The qualification shall remain valid for 2 years provided there is certified

confirmation of welding to the WPS in that time.

A Welder‟s Qualification Certificate automatically expires if the welder has not

used the welding process for 6 months or longer.

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Welding Engineer writes a preliminary Welding

Procedure Specification (pWPS) for each test weld to be

made

• A welder makes a test weld in accordance with the pWPS

• A welding inspector records all the welding conditions used

for the test weld (referred to as the „as-run‟ conditions)

An Independent Examiner/ Examining Body/ Third Party

inspector may be requested to monitor the qualification

process



The finished test weld is subjected to NDT in accordance with

the methods specified by the EN ISO Standard - Visual, MT or

PT & RT or UT

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Test weld is subjected to destructive testing (tensile, bend,

macro)

The Application Standard, or Client, may require aditional tests such as impact tests, hardness tests (and for some

materials - corrosion tests)


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

• The welding conditions used for the test weld

• Results of the NDT

• Results of the destructive tests

• The welding conditions that the test weld allows for production welding

The Third Party may be requested to sign the WPQR as a true

record


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An approved WPS should be available covering the range

of qualification required for the welder approval.

• The welder qualifies in accordance with an approved WPS

• A welding inspector monitors the welding to make sure that the welder uses the conditions specified by the WPS

EN Welding Standard states that an Independent Examiner,

Examining Body or Third Party Inspector may be required

to monitor the qualification process

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The finished test weld is subjected to NDT by the methods

specified 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 conditions used for the test weld and the range of qualification allowed by the EN Standard for production welding

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


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

which the welder should have or have access to a copy of !

• 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

wps welder qualifications section 5

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