Procedure qualification as per ASME IX

Date 12-06-2007 09:30

I received a WPS supported with 2 pre-qualified PQRs recently from my sub-contractor,

1st PQR - which qualified a butt joint (not T-joint) with 10mm plate welded to 40mm plate with 2 welding processes.
The 2 welding processs used are GTAW (from root 5mm thick) and SMAW (ther remaining 5mm).

2nd PQR - which qualified a but joint with 40mm plate to 40mm plate which also 2 welding processes.
the 2 welding processes used are SMAW (from root 20mm thick) and SAW (the remaining 20mm).

My sub-contractor intended to use this WPS to qualify
1. Base material thickness from 5 - 200mm as per ASME IX QW 451.
2. Weld metal thickness GTAW - max. 10mm and SMAW - max. 200mm

From my interpretation, the 1st PQR should be the same as 10mm welded to 10mm although one side was using 40mm. (this qualification is funny to me
although both of them are certified by authorised inspector), accordance to ASME IX QW 451. this PQR should only qualified base metal thickness max. 20mm,
which cannot be used to support a WPS with base metal thickness up to 200mm. Please advise if my point is wrong because my sub-contractor does not
agreed with what i commented. thanks alot.

By Shane Feder (****)

Date 12-08-2007 12:43

Noel,
If you look at QW 200.4 (b) it pretty much answers your question.
Sorry I can't give more of an explanation at the moment but I am in a cosy relationship with a bottle of Tanduay rum (Philippino) at the moment,
Regards,
Shane

By Noel Tan (**)

Date 12-11-2007 00:53

Thanks, but it does not give me any answer,
or i try to ask in this way, can u qualify a butt joint welding procedure using 10mm to 40mm plate with weld thickness of 10mm?
if u say can, then may i know what is the range of base metal thickness qualified?

By Shane Feder (****)

Date 12-12-2007 08:40

Noel,
If the contractors first PQR (10 mm) is not 13 mm thick minimum as per QW200.4 (b) then it cannot be combined with a second PQR of greater thickness to give coverage from 5 - 200 mm.

(b) For GTAW, SMAW, GMAW, PAW, and SAW,
or combinations of these processes, a PQR for a process
recording a test coupon that was at least 1⁄2 in. (13 mm)
thick may be combined with one or more other PQRs
recording another welding process and any greater base
metal thickness. In this case, the process recorded on
the first PQR may be used to deposit the root layers
using the process(es) recorded on that PQR up to 2t
(for short-circuiting type of GMAW, see QW-404.32)
in thickness on base metal of the maximum thickness
qualified by the other PQR(s) used to support the WPS.
The requirements of Note (1) of QW-451.1 and QW-
451.2 shall apply.

Hope that helps,
Regards,
Shane

By Raju Vairamani Date 12-21-2007 03:49

1) I fully agree with shane's opinion. to cmbine 2 pqrs, the minimum thickness shall be 13mm.
2) Secondly you have not mentioned about the PWHT and/or Impact test requirment by refrencing code (like ASME b31.3, 31.1 sec viii div-1) which are essential variable and maximum qualified thickness limit are restricted.
3) If above is applicable then refer to indivual cross reference from the table QW-253 for SMAW and QW -256 for GTAW

hope this will help you to some extent.
Rgds
Raju Vairamani

By toddler (**)

Date 12-18-2007 07:26

Noel,

The way I see it, your subcon WPS is not qualified.

1st: You are correct to say that the 10:40mm combination qualifies only a max of 20mm (max weld deposit)
2nd: You can't use one or more PQR thicknessess as additive (QW-200.2 (f)); you can only use it separately to cover the min/max range (same process variables)
3rd: The 2nd PQR qualifies SMAW for a max of 40mm only (being the deposited weld metal is only 20mm)

A GTAW/SMAW WPS that can be qualified by these 2 PQR's will be 50mm thick combined (GTAW:10mm max / SMAW:40mm max). This is assumming that the root will be 10mm by GTAW which may not be in actual welding. The root will normally be 2 passes only (about 5mm) and if you apply the max thickness of SMAW, you may be able to weld a max of 45mm only material thickness only

Note: The material thickness by SAW process does not count here (deductive)

Ciao!