Combination of two individual PQR with individual process

By pipewelder_1999 (****)

Date 06-25-2008 12:34

There is Nothing that prohibits this provided both procedures are qualified by testing. In addition, there is nothing that prohibits you from welding one part of a joint with one WPS and the Other part of a joint with another WPS. If there is, I have missed it.

Have a nice day

Gerald Austin
www.weldingdata.com

By 3.1 Inspector Date 06-25-2008 14:36

I dont know anything about D1.1 :(
But are you sure you can use 2 different WPS' for one weld?

By pipewelder_1999 (****)

Date 06-25-2008 15:17 Edited 06-25-2008 15:22

There is nothing that I can find that indicates you cannot. I may not have been looking in the right places. I am open for correction on this one.

There is NOTHING that I am aware of that prohibits me using any weld procedure from welding on a joint or any part of a joint as far as codes go.

If for instance I weld a joint partially up with GTAW and Stop. I have a single VEE groove with Weld Metal as backing. Provided the next WPS is qualified for that and all other variables for the joint, the WPS is qualified.

For convinence and reduction in paperwork, one document would be the way to go however if two were used, I would have a hard time telling someone that was wrong. ASME and AWS D1.1 do not seem to have any statment that would prohibit this.

Gerald

By 3.1 Inspector Date 06-25-2008 15:25

You might be right....

By Shane Feder (****)

Date 06-25-2008 20:50

Morning guys,
Initially I was a bit confused because I had always thought you could use a combination of PQRs to format a single WPS but I did not think a combination of WPSs was acceptable.
However, a bit of research and it is indeed acceptable.

AWS D1.1 Section 3.6.1 Combination of WPSs. A combination of qualified and prequalified WPSs may be used without qualification of the combination, provided the limitation of essential variables applicable to each process is observed.

ASME IX Section QW200.4 Combination of Welding Procedures. (a) More than one WPS having different essential, supplementary essential or non-essential variables may be used in a single production joint. Each WPS may include one or a combination of processes, filler metals or other variables.

Hope that helps,
Regards,
Shane

By 3.1 Inspector Date 06-26-2008 06:14

Interesting :)

By Kix

Date 06-26-2008 13:01

Ya know how they say not to GMAW weld over SMAW for general reasons? Well, could you legally if you had a PQR for SMAW 1G plate and a PQR for a 1G GMAW plate? I mean, run a root and fill pass with SMAW and finish it out with GMAW if you had 2 PQR's. I know this isn't the same situation as the threads posters, but if you could do what he is asking, couldn't you technically do this as well?

By pipewelder_1999 (****)

Date 06-27-2008 04:04

I have never heard of that. Only the FCAW-SS mentioned below. I tried it with GTAW, SMAW and GMAW. None of them weld over FCAW-SS when I use E71T11. Howver the 71T11 could weld over the others fine.

I have never read anything in the codes prohibiting the intermixing of processes. I have always avoided the FCAW SS because of actually trying to do it back in the early 90's.

By Richard Cook (**)

Date 07-01-2008 01:56

Check AWS D1.8 section 6.3.4,where intermixing any other process with FCAW-S, it will require qualifying. The problem comes into play with your toughness, you would have to do additional CVN. This is applicable with the seismic provisions and has been found to greatly affect the required toughness.

other than this, with AWS you could combine two different processes as long each process is used within the limitations of that WPS (AWS D1.1 3.6.1).

By pipewelder_1999 (****)

Date 07-01-2008 13:50

I was referring to the codees I was familar with. I guess I should have clarified. Isn't toughness an issue with SOME of t he FCAW-SS wires regardless of mixing ?

By Richard Cook (**)

Date 06-26-2008 12:56

There is one instance in AISC/ AWS dealing with intermixing of weld metals you need to watch for. FCAW-S with other processes in the seismic provisions requires qualification. so make sure of the standards called out in the contract. This is one instance I know that you just can't combine WPS.

By MDG Custom Weld (***)

Date 06-27-2008 12:45

For what it's worth, my $.02

I would think that to have a proper PQR for the second process, it would have to already been welded with the first process, then welded with the second process, then tested. Example: If you had a PQR for tig root on a specific joint, you weld the root as described and test the part. Then if you had a PQR for SAW fill/ cap, you would weld the tig root and fill as described and test the joint. You could combine the WPS's for both to give you the complete weld, however some essential variables are different for each process. This seems like it might make the combined WPS somewhat "busy" in terms of wording. I would process it as two WPS's for one joint just because of the multiple processes used. Our numbering system also uses certian number strings for each process to help the welders i.e. 1000 is GMAW, 2000 is GTAW, 3000 is FACW, and so on.

By pipewelder_1999 (****)

Date 06-27-2008 16:00

There is no need to weld the 1st part of the couopon waith a specific process. Ther is no variable such as "Previously Used Welding Process" or "Backing Filler Metal Class" for ASME Sec IX or AWS D1.1.

The self shielded FCAW process is "Special" in the fact that the elements used to shield the puddle build up rapidly. That is one of gthe reasons the manufacturers limit the the thickness to be deposited.

Some of those elements just don't mix with other elements. FEMA is indicated to have addressed some of these issues. See this article http://www.aws.org/wj/mar02/feature2.html .

I am not aware of D1.1 or ASME Sec IX restricting the use of mulitiple procedures on one joint or multiple processes. Obviously there is some responsibility on the part of the manufacturer to know what is prudent for fabricating. Just because the code allows something or does not, does NOT mean its a good idea.

The codes are not a replacement for people familar with welding or a good quality systems. There just books so everyone can go to the same source to argue :)

By MDG Custom Weld (***)

Date 06-27-2008 17:56

Gerald, Your point makes total sense. I agree that there is no "previous Process" variable identified in the codes. My question now becomes how could you qualify the PQR for the example of a GTAW root SAW fill/cap? If the fill/cap is done without the GTAW root, obviously is will fail and the same for the root without fill/cap.

By pipewelder_1999 (****)

Date 06-27-2008 18:18

A WPS would be qualified for that process any number of ways. You could

1) Perform a PQR with GTAW and SAW and create a WPS that gives the option of using GTAW OR HAVING other Backing such as a strip or backgouged.
2) Perform a PQR with GTAW and one with SAW and the writing a WPS with both process.
3) Use an already qualified WPS for GTAW for part of the Joint then weld the remainder of the joint with SAW using a procedure that MAY or MAY NOT refer to the backing type.
4) Perform a PQR with GTAW/SMAW and write two seperate WPS's that may or may not be combined on a production joints.

And many more combinations. Bear in mind that ASME and AWS D1.1 have very different rules regarding what is allowed for qualifying a welding procedure.

By Bka

Date 06-27-2008 16:03

Thank for all of your response,

I think that even both of individual PQR also passed mechanical test and you combinate them together to support for one WPS . it is nothing to make sure that weldment achieved the mechanical property well. Because weldments are never demonstrated by mechanical test.

Bka.