Welder qualification: Base metal substitution QW-423

Date 07-14-2009 16:56 Edited 07-14-2009 17:07

ASME Code Section IX
Paragraph QW-350, QW-356
Essential variable QW-403.18

We have a qualified welding procedure (WPS-A) to weld pipe, 6G, GTAW, P8 to P8

Is it permited by the BPV IX to qualify a welder substituting the base metal of a qualified WPS-A in accordance with QW-423; in our case, changing the base metal from P8 to P1 for welder qualification?

is the welder qualified for WPS-A?

In other words, we have a qualified WPS-A, I want to qualify a welder according to that WPS-A, however I want to change the base metal (P8 for P1) as permitted in QW-423. Is this my interpretation correct?

Do somebody know the intent of ASME Sec. IX paragraph QW-423?

By js55

Date 07-14-2009 17:11

When you really stop and think about the logic of the base metal substitution allowance there really isn't any other way to think about it. Most people do not normally qualify procedures wherein they weld say a nickel alloy with carbon steel wire or a carbon steel alloy with nickel base wire. So the material combination to explicitly allow the performance qual will probalby not exist. And therefore the substitution would have to apply in a manner that would not be specifically addressed in the existing WPS or the BM sub would not make any sense.

By cremx

Date 07-14-2009 19:17 Edited 07-14-2009 19:24

Thanks js55 for your comments, essentially I agree with you in terms of the common sense, but sometimes there are people that interpret or use in their benefit the code allowances. (Not me)

BTW; the idea is to qualify a welder per ASME BPVC Sec IX; thinKing in the purpose for welder qualification....QW-301.1 Intent of Test. The performance qualification test are intended to determine the ABILITY of welders and welding operators to make SOUND WELDS.

Does the base metal change makes differences in the ability or affect the sound of the weld?, I think the intent of QW-423 is to substitute the base metal, says P8 for any other P8, or P1 for any other P1; I think it works in that way, but some people intepreting in different way...

By js55

Date 07-14-2009 20:37

The code committee guys are very well aware of the fact that carbon steel will be used to qualify for welding on nickel base alloys or stainless steels or CrMo's etc.
Does the base metal make a difference? Yes
Does the use of alternative base metals demonstrate ability as accurately as the matching base metal? No.
Does this matter? Some say yes some say no.