Does the welder for Welding Process Qualification testing Be Qualified?

[mrmalcolm]

Do test piece for Welding Process Qualification testing need to be carried out by qualified welders? Is it allowed that test piece weled by unqualified welders? Thank you.

 

[gtaw]

The test assembly used to qualify the welding procedure specification can be welded by a welder that was previously qualified or it can be welded by a welder that has never been qualified. Per most American welding standards, the welder that welded a test assembly that passes all the requisite tests (NDE and mechanical) is "automatically" qualified by virtue of welding an acceptable test assembly. The testing regiments for qualifying the WPS is typically more involved and extensive than the testing required to qualify the welder.

 

[racookpe1978]

On two levels, it can hardly be otherwise: A welder cannot "be qualified" on a WPS test weld if that WPS itself is not yet qualified.

On the other hand, should YOU (your company) always chose your best welder (of those available) to make the certification welds for a new WPS?

Your "best welder" will find ways by his or her skills and hands-on knowledge to make a "bad WPS instructions and requirements" pass the strength and bend requirements. But a "common welder", one less experienced or one who represents your "average welder" will "test the procedure" better by revealing problems or restrictions or PWHT or inclusions or weld prep access problems.

Obviously, you do not want to "just grab the cheapest, least experienced guy from the line" to work on verification of a new WPS. An incompetent or poor welder will screw up a valid WPS just as easy as he or she can screw up a 50 year old procedure. But, in truth, you do write and approve every WPS to "verify that it will produce good welds" if used properly.

 

[gtaw]

The following is taken from AWS D1.1:2020 Structural Welding Code/Steel
"6.16.3 Welder and Welding Operator Qualification Through WPS Qualification: A welder or welding operator may also be qualified by welding a satisfactory WPS qualification test plate, pipe, or tubing that meets the requirements of 6.10. The welder or welding operator is thereby qualified in conformance with 6.16.1 and 6.16.2."

The conditions noted above is pretty standard for many American welding standards.

 

[mrmalcolm]

On two levels, it can hardly be otherwise: A welder cannot "be qualified" on a WPS test weld if that WPS itself is not yet qualified.

On the other hand, should YOU (your company) always chose your best welder (of those available) to make the certification welds for a new WPS?

Your "best welder" will find ways by his or her skills and hands-on knowledge to make a "bad WPS instructions and requirements" pass the strength and bend requirements. But a "common welder", one less experienced or one who represents your "average welder" will "test the procedure" better by revealing problems or restrictions or PWHT or inclusions or weld prep access problems.

Obviously, you do not want to "just grab the cheapest, least experienced guy from the line" to work on verification of a new WPS. An incompetent or poor welder will screw up a valid WPS just as easy as he or she can screw up a 50 year old procedure. But, in truth, you do write and approve every WPS to "verify that it will produce good welds" if used properly.

Thank you for your reply. Would it be more appropriate to choose a moderately skilled welder( (with or without a welding qualification certificate) to weld the WPS test assembly?
Best regards

 

[weldstan]

It's advised that your better, more experienced welder perform a new welding procedure qualification. As gtaw stated, succesfull qualification of the WPS automatically qualifies the welder under ASME IX. Our company primarily used one welder who was qualified for all of our welding processes to qualify a new welding procedure for whiich he was not previosly qualified. The WPS to be qualified was written by a company employed Welding Engineer to provide the welder all the information he would need to be successful. Additionally the Engineer would discuss with the welder all the welding parameters required to be successful and the welder would be able to make trial welds in accordance with the proposed WPS before quaification thereof. Tweeking of the WPS could be done during the trial phase before final qualification. There was more than one case when another experienced welder attempted qualification of a new WPS and failed, requiring another qualification attempt supervised by the Welding Engineer.

 

[gtaw]

It's the old, "What comes first, the chicken or the egg?"

Always have the welding of the test coupon witnessed by someone that understands welding and what is being accomplished. They should be independently verifying what is being done is in accordance with the preliminary WPS. The should also record the welding variables and parameters. Material - is it the right "stuff", heat numbers, CMTR, etc.
Process - if GMAW is it the correct transfer mode
Joint detail - groove angle, root face, backing, etc.
Shielding gas - is it used, what was the % of gases in the mix, flow rate
Filler metal - specification, classification, diameter, manufacturer, etc.
I'm always amazed at the number of times the base metal isn't what was specified or the filler metal is not what was called for.

Preheat
Post weld heat treatment - yes or no? If yes, details of the PWHT

I could go on, but you get the idea.