ASME Section IX, QW-423.1 Question

Date 07-30-2004 14:22

Does this section imply that if a welder qualifies (performance) on carbon steel pipe (P1), he/she is also qualified to weld the base materals shown to the right (assuming the other essential variables allow this)?

Example: If a welder qualifies on GTAW Carbon pipe (no backing gas used)....can he/she weld GTAW Stainless pipe (P8) which requires argon as a backing gas. QW-356 shows the deletion of backing gas is an essential variable but "adding" is not. The filler classification for both are F6.

Am I correct with this understanding?

By GRoberts (***)

Date 07-30-2004 14:39

Yes

By dlmann

Date 07-30-2004 22:09

Notice how the P-Numbers are listed on Base Metal(s) used for welder qualification. Take a pen and place a line all the way accross, both above and below the "P-No.21 through P-No. 25" and you'll have a useful chart.

By tab_1999 (**)

Date 02-04-2005 18:27

May save you some grief!
I work for an WorldWide EPC company and manage the Construction Quality Control program at specific sites.
There are a lot of folks that are awesome welders with GTAW on carbon steel that are absolutely clueless on stainless steel. ( A Lot )
This is the reason that (even though) ASME categorizes these together, we conduct separate ss pipe tests, especially on Schedule 10 or thinner. Being proactive with this saves a lot of rework and embarassment by making this a site specific requirement.

Good Luck

By dlmann

Date 02-04-2005 20:38

Tom: Good point. The skill of the welder must be taken into account. I have two examples at my site. The first example at my site, is plate versus pipe welding. Even though a plate qual certifies down to 2-7/8 OD (ASME IX), we have a couple of welders who have a lot of trouble welding that small and smaller. On plate and larger diameter pipe they do fine with no rejects. We recommend that these welders qual on plate and pipe.

The second example is the heat resistant SS, P8 group 2 (RA-253) RA-253 AC/DC filler metal and SS, P8, 316/308/309 types E3xx filler metal. SMAW process. They require seperate WPS's because of the filler metal but a lot of people think that because they are both P8 and SMAW any welder should be able to weld them.

Of course we have our "go to welders" who can weld anything in any position. As a project, they make us look good.

Regards and have a good weekend, Donnie Mann

By jon20013 (*****)

Date 02-04-2005 20:56

Tom, we do the same thing in my small company. On rare occasion I will take the latitude provided in QW-423 but I have found as you have found (in general terms); a welder who can weld great on carbon may or may not do so great on stainless. Same thing for the nickel alloys. However, from an employers standpoint I am very glad the code gives me the latitude to make that decision of whether or not to test him/her on additional alloys.