Multiple Process WPS

[MathGuy]

Does Section IX or D1.1 prevent the combining of multiple PQRs, one with PWHT and another without, from qualifying a WPS. A reference paragraph would be greatly appreciated.

 

[vesselfab]

Does Section IX or D1.1 prevent the combining of multiple PQRs, one with PWHT and another without, from qualifying a WPS. A reference paragraph would be greatly appreciated.



THAT'S WHAT HE ASKED....I THINK

 

[DVWE]

HE'S NOT ASKING IF YOU CAN MAKE THAT IN ONE WELD, HE'S ASKING IF YOU CAN COMBINE PQRS INTO ONE WPS!

 

[metengr]

Does Section IX or D1.1 prevent the combining of multiple PQRs, one with PWHT and another without, from qualifying a WPS. A reference paragraph would be greatly appreciated.

Reply; For Section IX application, No.

Rationale; Refer to Section IX, QW-200.2 (f). Multiple PQR's
with one WPS...

A single WPS may cover
several essential variable changes as long as a supporting
PQR exists for each essential and, when required, supplementary

 

[vesselfab]

Well, guess I am wrong then

But will continue to not use mixed essential variable pqrs
to qualify a procedure.

I just can not see it as advantageous to do so.

 

[GRoberts]

DVWE,
Yes, I have personally done this and seen it done by others. The main situation I have found it advantageous for is repair projects. If you are doing a bunch of repairs that do not require PWHT, but then later, a find one that requires PWHT, you don't have to go back and question all the previous repairs when you PWHT the entire part. Another situation where it make life simpler, is pipe welding. If you are welding pipes of several diameters, some which require PWHT and some that don't you don't have to keep switching welding procedures back and forth. It is mistake-proofing which WPS to use.

 

[DVWE]

GRoberts,

I appreciate your feedback. Again I say, whatever works best for the shop.

 

[Mr168]

GRoberts nailed it, especially for field welding applications.

We roll them into single WPS's for all of our field fabricated pipe. The fewer WPS's you let out into the field, the less confusion among foremen, welders, QC and rod room attendants.

We frequently take advantage of the exemptions in B31.1. Take carbon steel for example. We have a procedure qualified up to 8 inches, we use the same WPS for all of our P1 materials, but we have the option of eliminating PWHT (typically) for welds under 3/4" thickness. The welders themselves do not initiate PWHT, so there is no real confusion. In the field, separating them would serve no meaningful purpose.