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Procedure/welder qualification



donswheel
08-12-2008, 08:13 AM
If a company has numerous WPS's and PQR's approved for use in the plant does this require the need for each welder to be certified to each WPS or does the welder qualification testing (Say all positions unlimited plate groove) qualify him for all WPS in plant? Heres another question, If my qualification tests specify a backing strip does that disqualify the welder for WPS that doesn't use backing strips?

Gaustin
08-12-2008, 08:33 AM
Hello,

The welder qualification ranges are entirely inrelated to the WPS's.

When a welder performs a test weld, he qualifies based on a set of variables used during that test. The allowed ranges after that test are listed in the applicable code book. A welder only uses a WPS while testing. Depending upon the test taken and the ranges of the other WPS's he may or may not be qualified to use them.

The variable ranges for WPS's can cover quite a bit of area or be very restrictive. That is dependent upon how it was qualified while welding the "PQR-Procedure Qualification Record".

The welder will need to be requalified for welding if the production weld he is to make has ranges that are outside of his ranges allowed by the rules for welder performance qualification testing. The WPS has no bearing on the need to retest.

The WPS needs to nbe requalified if the production weld it will be used for has ranges that are outside of the ranges allowed for qualification of welding procedure specifications.

A common misconception is that a welder is "Qualified to a WPS". That is incorrect. Here is an example. For ASME Sec IX, a WPS can be qualified for welding pipe by using flat plate unless impact testing is a requirement. The welder can take two pieces of carbon steel and weld them together using GTAW and ER70S-2 wire. The plate can be flipped over and backgouged and the second side welded.

After all of the tests in accordance with the code are done, you can write a WPS for welding pipe or plate using GTAW for thicknesses up to 1" in all positions and ALL diameters of pipe. With or without backing.

The welder that welded the PQR is allowed to weld using the wps that was written above however he is limited to flat groove welds and flat or horizontal fillet welds. All groove welds MUST have backing. So in that case, he is qualified to use the procedure.

IN ADDITION, that welder is also qualified to weld stainless steels and many other alloys using ER3XX filler metal (308,316,347,312 etc) . Also the welder is allowed to wel on material of ANY maximum thickness and deposited weld metal thickness.

The WPS that was qualified has ranges that the welder may not be qualified for. The welder while welding the PQR, may be qualified for ranges that are outside the range of the WPS.


Hope this helps.

Gerald
http://www.weldingdata.com

donswheel
08-12-2008, 12:12 PM
Gerald you are a wealth of information. I am printing out your response so I can study it thoroughly. If I got this right, so long as the parameters of the WPS are within the ranges for the welder in accordance to his certification testing then he is qualified to weld that particular WPS. Right?

Gaustin
08-12-2008, 12:30 PM
Thats correct. There may be codes of construction that specifiy otherwise. I just haven't come across them yet.

Just remember that Welder Certification and Welding Procedure certification have seperate rules and ranges.

Though the statements such as "My welders are certified to weld with procedure xxxxxx" or "I am certified for xx procedures" are not forbidden , they can be misleading.

ASME and AWS specifiy how welders and procedures are qualified. Both organizations seperate the performance requirements and procedure requirements.

Though the codes are "rules" whan referred to by contract, they are not a replacement for good design, engineering, and quality systems. In some cases tighter controls may be a value to a company.

Have a good one and thanks for the comments.

donswheel
08-12-2008, 02:10 PM
Thank you. One has to appreciate a forum where knowledgible people are willing to give their time and expertise to others. I really appreciate it.