QW 200.4(b) of ASME 9 1

[athilatt]

Hello Every one..

Could any body explain me the exact interpretation of QW 200.4(b) of ASME Sec 9. Is this with regards to Root layer qualification only? How this can be done? Or this is just write a WPS out of PQRs,or run PQRs...

 

[metengr]

athilatt;
In basic terms, QW-200.4 (b) describes the use of multiple PQR's to support a multi-process WPS provided the coupon for the PQR is ½” or greater in thickness. Yes, this paragraph can be used for root deposits, as one example, where one PQR with a coupon at least ½” in thickness was welded with one or more processes recorded could be used for the root up to 2t thickness, where a second PQR recorded using another one of the processes listed in QW-200.4 (b) is completed to fulfill the base metal thickness qualification for the WPS used, and both of these PQR’s support a multi-process WPS.

 

[DVWE]

I guess you're still struggling with this a little. I'll try to explain the best I can.

Let's say you have a production joint which is 8" thick, and you want to weld it with 2 root layers of GTAW and SAW remainder.

The best way to qualify this, using the limitations of QW-451 is to do a 1-1/2" thick SAW coupon which qualifies up to 8", and a 1/2" thick GTAW coupon which qualifies the root passes on the 8" thick production joint.

QW-451 otherwise prevents the use of the GTAW on the 8" thick production joint, because it was done on a 1/2" thick coupon. Therefore, you can only weld up to a maximum of 1" thick in production. However, QW-200.4(b) allows the use of the GTAW for root layers if used in conjunction with other PQRs that are qualified for 8". Does that help?

 

[athilatt]

metengr,DVWE.
Its really thrown light in right area..thanks

DVWE
Then, is it conflicting with QW 200.2(f)?..
200.2(f)states-- "[e.g.,a single WPS may cover a thickness range from 1/16 in(1.5 mm)through 1 1/4in.(32 mm)if PQRs exist for both the 1/16in.(1.5 mm)through 3/16in.(5 mm) and 3/16 in.(5 mm) through 1 1/4in.(32 mm) thickness ranges]

OR is QW 200.2(f)meant for thickness upto 32mm(?) only..

 

[DVWE]

No. QW-200.2(f) is an example only. And I believe in that example, it is referring to the SAME welding process (one FCAW PQR qualified for 1/16" - 3/16" and the other FCAW PQR 3/16" thru 1 1/4" and now you have a single WPS qualified 1/16" - 1 1/4").

When you write your WPS for your case, just limit your GTAW for root passes only. You're already qualified to 16mm, both base metal (T) and deposited weld metal (t). There's nothing in the code that says you can't further limit either one. So just limit GTAW for root pass only, and then specify SMAW for remainder.

 

[athilatt]

DVWE,

Yes, Now I could follow what you are specifiying..

One last clarification..
If my one PQR(GTAW) qualified on 5mm thick and other one(SMAW) is 10mm...Then is it possible to club these two PQRs for welding a Production joint 20mm, if I write a single WPS with clubbing these PQRs(GTAW+Smaw)?

I think,No..
Am I right..

 

[DVWE]

You are correct, you cannot do that.