Qualifying a WPS from multiple PQR's
Qualifying a WPS from multiple PQR's
(OP)
Hi guys,
hope someone can offer some advice here. What I would like to know is if there is a limit to the amount of PQR's which can be used for a single WPS? We are doing a project for the offshore sector, and have recently had a contractor who had quite a complex weld to do. In their WPS they listed 10 different PQR's as qualifying this document. I was amazed that they would do this, but I could find nothing to argue against it. They maintain this practice is ok.....
Any opinions or advice....
We mostly work to DNV/GL rules, but would take guidance relating to any spec..
regards
Declan
hope someone can offer some advice here. What I would like to know is if there is a limit to the amount of PQR's which can be used for a single WPS? We are doing a project for the offshore sector, and have recently had a contractor who had quite a complex weld to do. In their WPS they listed 10 different PQR's as qualifying this document. I was amazed that they would do this, but I could find nothing to argue against it. They maintain this practice is ok.....
Any opinions or advice....
We mostly work to DNV/GL rules, but would take guidance relating to any spec..
regards
Declan





RE: Qualifying a WPS from multiple PQR's
(f) Multiple WPSs With One PQR/Multiple PQRs With
One WPS. Several WPSs may be prepared from the data
on a single PQR (e.g., a 1G plate PQR may support WPSs
for the F, V, H, and O positions on plate or pipe within
all other essential variables). A single WPS may cover several
sets of essential variable ranges as long as a supporting
PQR exists for each essential and, when required,
supplementary essential variable [e.g., a single WPS may
cover a thickness range from 1/16 in. (1.5 mm) through
11/4 in. (32 mm) if PQRs exist for both the 1/16 in.
(1.5 mm) through 3/16 in. (5 mm) and 3/16 in. (5 mm)
through 11/4 in. (32 mm) thickness ranges].
RE: Qualifying a WPS from multiple PQR's
This probably should be part of another thread, but how can this be controlled. What I mean by this is that differently qualified procedures will use different weld settings, and most importantly different heat inputs...Is there any way to tell whether by using all these PQR's (each of which has successfully been qualified), that the interaction of them all together will give the required strength and impact properties required....
Declan
RE: Qualifying a WPS from multiple PQR's
RE: Qualifying a WPS from multiple PQR's
Agreed with your comments.
One vendor of mine throws in PQR's that are not relevant, e.g. wrong process, heat treatment, materials, etc. that don't in any way, in whole or part, support the WPS. His reward is the WPS gets summarily rejected. Supplementary and Supplementary Essential variables for all PQR's must support the WPS. If not, the WPS is not valid.