WPQ 2

[DCMV]

I need help to understand the statement made in ASME Sect IX it basically states that If a welder or welding operator qualifies in combination on a single test coupon the welder can weld in production any of his single processes or combination of his processes. So if he completed a 2" sch160 in 6G position using GTAW as root pass/hot and complete filler/cap with SMAW he should then be qualified to weld either SMAW only or GTAW only or he could use SMAW for root and hot and GTAW for fill and cap right?. So my question is why would his WPQ range limit him to use no backing on GTAW and Backing on his SMAW? Is that just a mistake on the person that completed the WQR? Should the WPQ state with or without backing? Your help would be greatly appreciated thank you.

 

[XL83NL]

IF you have a root pass made using GTAW, and continue SMAW, you're basically welding SMAW with backing.
Root passes count as backing. Hence one is not qualified for SMAW welding without backing, as backing is an essential variable in SMAW.
Refer to QW-353 -> QW-402.4;

QW-402.4 The deletion of the backing in single-welded groove welds. Double‐welded groove welds are considered welding with backing.

 

[birken]

VanChe,

I would advise you to use WeldPulse software which would help you in getting and knowing about the approval ranges for both SMAW & GTAW processes considering procedure or performance qualifications.
You can know more about the software at

http://www.weldpulse.com

Not a hefty amount of money required to get this software and it helps in real quick evaluations on different fronts of welding other than qualifications too like welding cost & economy, predicting ferrite number etc.

Birken

 

[XL83NL]

Buying software is not the best and most successful way in understanding a Code and its principles.
I would suggest not to buy birken's suggested software, but buy ASME IX (if you dont own a copy yet), or start studying it to get familiar with it.

 

[weldtek]

I would second XL's suggestion. The best way to learn Code requirements is to have the Code book and more importantly, use it. If you feel you need some additional help there are several guide books that can be purchased as well as ASME sponsored courses.

 

[DCMV]

I understand that Backing is an essential variable and the GTAW root pass is considered backing for the SMAW, but I don't understand why the statement would be made in QW-306.
QW-306 COMBINATION OF WELDING PROCESSES:
A welder or welding operator
qualified in combination on a single test coupon is
qualified to weld in production using any of his processes
individually or in different combinations, provided he
welds within his limits of qualification with each specific
process.
So the so called Super coupon would not cover the multiple process as perceived, because the SMAW process could not be used as a single process, only the GTAW could be used as a single process and that would depend on the weld metal thickness deposited.

 

[XL83NL]

You can still use SMAW as a single process, but iT requires you to use a backing material, like a strip, to make the root pass.

 

[weldtek]

Van - You copied the answer to your question;

'provided he welds within his limits of qualification with each specific
process.'

 

[gtaw]

Maybe a little clarification will help.

The welder welds the test coupon in the required position with GTAW for he root bead and the second layer. No backing is used. As a result of passing the test, the welder is qualified for welding joints in the position tested and any others permitted by the code for that test position. The welder is also qualified to used GTAW in production welds that utilize backing or those that do not utilize backing, i.e., open root joints. The thickness for which he is qualified is based on the thickness of he weld deposited with GTAW.

The test coupon was not welded completely. Several additional weld layers are needed to complete the test. The welder can complete the test with GTAW in which case he is only qualified for GTAW. As an option, the welder can elect to complete the test using a different welding process. In this case the welder elected to complete the weld using SMAW. Since the root and second pass are already in place, the remaining weld completed with SMAW is considered to be welded with backing. That is, the root and second layer served the function of backing for the subsequent weld deposited with SMAW. The welder is now qualified for SMAW if backing is used and the thickness is based on the thickness deposited using SMAW.

The welder is not qualified for GTAW with or without backing, but limited by the thickness deposited with that process. The welder is also qualified for welds deposited with SMAW, but he is limited to welds made with backing and limited by the thickness deposited with that process. He is limited by the base metal used, the F number of the filler metal/electrode, the position tested, and the weld type (groove versus fillet).

The welder can weld using only GTAW with or without backing. He can weld with SMAW, but only if backing is utilized, or he can use a combination of both GTAW (with or without backing) and SMAW, but only if there is a backing weld deposited by GTAW (remember, he is using both GTAW and SMAW on the same joint.

Hope this helps.

Best regards - Al