wps welder qualifications section 5
TRANSCRIPT
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
Welding Procedures 5.2
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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
Welding Procedure Qualification 5.3
Production welding conditions must remain within the range of
qualification allowed by the WPQR
(according to EN ISO 15614)
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Welding Procedure Qualification 5.3
(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 Procedure Qualification 5.3
(according to EN Standards)
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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Welding Procedure Qualification 5.3
(according to EN Standards)
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
Welding Procedures 5.3
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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Welding Procedures 5.3
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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Welding Procedures 5.3
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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
(according to EN Standards)
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
Welder Qualification 5.5
(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
Welding Procedure Qualification 5.7
(according to EN ISO 15614)
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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Welding Procedure Qualification 5.7
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)
(according to EN ISO 15614)
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
Welder Qualification 5.9
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(according to EN 287 )
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
Welder Qualification 5.9
(according to EN 287 )
• 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
Welder Qualification 5.10
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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