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Welder Performance Qualification (WPQ)


Welding Data >> Welder Performance Qualification (WPQ)

Welder Performance Qualification (WPQ)

Materials
The purpose of this test is to determine the welders ability to deposit a sound weld therefore the base material is not considered as critical as it is in the PQR. Hence a performance test on any material in P groups 1 to 11 approves all those groups and sub groups, also P34 and P4X (P40-P49). Providing a compatible consumable exists with the same F number used in the qualification test. (QW423.1)
Note a single sided weld is classed as a weld without backing and a double sided weld or weld with sealing run is classed as a weld with backing


Consumables

The F number cannot be changed without re qualification of the welder except that for performance qualification only using SMAW (MMA) F numbers up to and including 4 approve all lesser F numbers for double sided or welds with backing only. One Consumable from F41 To F45 approves any of these consumables, except SAW. Ref. QW404.11.
Note 'A' numbers do not apply to welder approval tests.


Variables

For each welding process there is a list of essential variables in QW352 to QW357 and QW360 for welding operators, these are not necessarily the same as the ones for the PQR. Essential variables cannot be changed. Explanations of all these variables is given in section IV of the code.


Diameter and Thickness Ranges

Diameter limits for all circular welds including groove welds, branch welds and fillet welds is given in QW452.3. there are no upper limits on diameters approved and pipe covers plate
Note for branch welds the diameter considered for the above limits is the one containing the weld preparation.
Thickness limits, groove welds. 
The thickness limit only applies to the deposited weld metal thickness not the plate thickness and any groove weld approves all fillet weld sizes.
For t greater than 12.5mm there is no restriction on the size that can be welded (Providing the test weld deposit contains at least 3 layers of weld).
 
Thickness limits, fillet welds. 
A test on plate greater than 3/16" approves all base metal thicknesses and fillet weld sizes ref. QW452.5. (Note the above diameter limits apply unless the fillet weld is qualified by a groove weld)


Joint Configuration

Joint geometry, a double V (or U) is considered the same as a joint with backing and does not qualify a single V (or U) without backing, but a single full penetration joint without backing qualifies all joint configurations.


Approval Range

Extent of approval is very well explained in QW461.9. Take particular note of welding positions which are also explained in QW461, for example to qualify a fillet weld in the normal horizontal-vertical position with a groove weld, the groove weld must be qualified in at least the 2G position. The welding positions defined in QW461.1.& QW461.2 should be referred to in the WPS. The position designations: 1G ,2G ,3G ,4G ,5G ,6G (Groove Welds) and 1F ,2F ,3F ,4F (Fillet Welds) are test positions


Period of Validity/Renewal of Qualifications (QW 322.2)

Providing the welder uses the process for which he is qualified and there is no reason to question his ability then his qualification lasts indefinitely.
If the welder does not use the welding process for which he is qualified for a period of 6 months or more then he must perform a new test in pipe or plate, any parent material, thickness and position, if successful all the welder approvals for that welding process are renewed in one test.


Testing Requirements

Test requirements for groove welds QW452 consists of either:-

  • One face bend and one root bend except for welding positions 5G & 6G which require 4 bends (Ref QW452.1 Note 4). If the plate exceeds 3/8" side bends may be used.  See QW 466 for precise details and exceptions.
    Note:- Bend Tests can in most cases be replaced by Radiography {See Below}. 
  • Radiography is optional and must be supplemented by bend tests when using GMAW (MIG/MAG) with dip transfer (Short Circuiting Arc) or when welding some special materials. Ref. QW304.
    Note:- Ultrasonic Examination in lieu of Radiography is not permitted

Test requirements for fillet welds in plate ref. QW452.5:- 

  • One macro section (QW 184) and One fracture test (QW182).

The location where each specimen has to be taken is defined in QW463


Radiography Ref QW 191

  • A length of at least 6" must be examined for plate or the entire circumference for pipe.
  • If the pipe circumference is less than 6" then more samples must be welded up to a maximum of 4. Ref QW 302.2.

Visual Examination Ref QW 302.2 & QW 190
Performance test coupons must show complete joint penetration with full fusion of the weld metal and base metal.
The welder performance test must follow a properly qualified W.P.S. Once qualified the welder must always work within the extent of approval of any properly qualified W.P.S. and his W.P.Q.
The welder who qualifies the P.Q.R. is automatically approved within the limits specified in QW304, QW305 and QW303. Ref QW301.2.


Specialist Processes

Such as corrosion resistant overlay or hard facing are covered in QW 453. 
Procedure variables are defined with all procedure variables in QW252 and in QW380 for welder approval. 
Min base thickness approved = size welded or 1", QW 453
Min Deposit Size Approved:- Point Where Chemical analysis taken No upper limit QW402.16 (462.5a) Welding Positions QW405.4 Performance Qualification approves all deposit thickness’ No min.QW381


 
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