Backing use in welder qualification test

Date 08-14-2003 22:56

According to AWS D1.1:98 section 4.23 qualification on joints with backing qualifies for welding production joints that are "backgouged" and welded from the second side. It´s logical due to any defect present at root joint is removed by grinding, then weld metal is deposited on the "sound backing weld". However, according to table 4.10 item (7) the omission of backing (if used in the WPQR test) shall require requalification. Our WPS stipulate backgouging the root joint before weld other side so, if we qualify a welder according fig 4.21 we shouldn´t requalify him if production welding have not backing. Am I rigth?

On the othe hand, I compare a WPS like a cooking recete. It says us step by step How and What I have to do, so I don´t understand why the only joint configuration for welder qualification is the figure 4.21? There are so many differents kinds of joints (there are so many dishes!!!) .
Look note 2 figure 4.22 for "welder operator qualification" it says: the Wps joint configuration may be used in lieu of the groove configuration shown, so why we cannot use our particular joint configuration for welder qualification?
thanks.
Miguel

By pipewelder_1999 (****)

Date 08-14-2003 23:52

Hello Miguel

If you qualify a welder with backing. He/She is qualified to weld with backing only. Omission of backing would require requalification. A double welded joint (Welded from Both Sides) is considered a joint with backing. A single welded CJP joint would require qualification.

Backing Strips or Welding from Both sides are both considered welds with backing. Therefore #7 would refer to omission of backing from a joint as would be the case in some CJP tubular connections in which the 2nd side does not have access. An example is indicated in para 4.26 (1) and (2).

If you test with a backing strip, you ARE qualified for all CJP grrove joints welded from one side with backing or welded from both sides.

Hope this helps.

Gerald Austin

By jwright650 (*****)

Date 08-15-2003 11:41

Hi Miguel,
You can test with any of the CJP joints to qualify your welders(I use a B-U4a in a 2G position in my shop[it represents the most common joint my welders will see], other shops use a B-U2a), provided you follow the guide lines in AWS D1.1:2002, Table 4.11 Welding Personnel Performance Essential Variable Changes Requiring Requalification, also see paragraph 4.22. which states:"Changes beyond the limitation of esssential variables for welders, welding operators, or tack welders shown in Table 4.11 shall require requalification."

So if "any" of the variables listed in this table have changed(omission of backing, Item #7), then a retest is necessary.

I know this code gets rather confusing when you get to reading it. That's what this forum is about, each of us look at this and try to determine what it is trying to convey to us. There are areas where we will all disagree on it's interpetation, but the "Commentary" in the back of the book helps with that. If there are paragraphs that you are confused on check in the back of the book. Annex B will give definitions to terms used also.
Hope to help,
John Wright

By jwright650 (*****)

Date 08-15-2003 13:00

Miguel,
I retract my first statement about using any CJP joint to qualify with, I also read in Table 4.10, Welder and Welding Operator Qualification-Number and Type of Specimens and Range of Thickness and Diameter Qualified, it gives the figure # to follow which tells you which joint configuration to use and I use the Optional joint in Figure 4.29 for Unlimited thickness in the Horizontal position(2G).

Now for WPS Qualification this is another story about joint configuration.
John Wright