ASME IX QW-200.4 confusing....

Date 05-12-2008 01:04

When I read ASME Interpretation as follow:

Background: A combination GTAW and SMAW WPS is supported by two PQRs. PQR A is welded
with SMAW to join 11⁄2 in. (38 mm) thick plates with 11⁄2 in. (38 mm) of SMAW deposit. PQR B is welded
with GTAW and SMAW to join 1⁄2 in. (13 mm) thick plates, with 1⁄8 in. (3 mm) of GTAW deposit, and
3⁄8 in. (10 mm) of SMAW deposit.
Question (1): Do PQRs A and B qualify the combination WPS for a base metal thickness range of 3⁄16 in.
(5 mm) to 8 in. (200 mm) when impact testing is not required?
Reply (1): Yes.
Question (2): Do PQRs A and B qualify the combination WPS for a maximum deposited weld metal
thickness of 1⁄4 in. (6 mm) for the GTAW process and 8 in. (200 mm) for the SMAW process?
Reply (2): Yes.

But when I read ASME QW-200.4(b) mention that "For GTAW, SMAW, GMAW, PAW, and SAW, or combinations of these processes, a PQR for a process recordng atest coupon that was at least 1/2 in. (13 mm) thick may be combined with one or more other PQRs....

Then you see it is contradiction, any body can Explain me for the confusion?

By js55

Date 05-12-2008 13:38

No. I don't see the contradiction.

By cong nguyen (**)

Date 05-13-2008 02:59

I see the GTAW only 3mm < 13 mm as per QW-200.4(b) requirement, so why do it can combine with PWRA?

By js55

Date 05-13-2008 13:13

If I understand you question correctly, the ability to combine the PQR's depends upon the thickness of the base metal, which in the case fo the GTAW PQR is at least a 1/2". Therefore it can be combined.

By cong nguyen (**)

Date 05-14-2008 01:40

Dear Js55,
So when we a going to combine two PQR, we concern about thickness of the test coupon, if the thickness of the test coupon > 13 mm then we can combine it? But in QW-200.4(b) I see "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)..." as you see, it mention "for a process" it mean that for each process. As above when PQR1 = GTAW (3 mm) + SMAW (10 mm) then GTAW is inadequate thickness to combine with other PQR, is it correct?

By sea Date 05-14-2008 09:53

dear freinds;
when you have more than 02 process you must take in consederation the deposite weld metal thikness (litle t max 2t qualified)
in our case my freindes
QW200.4 say
we can use pqr1 (test coupon T1) with max deposit weld metal qualified 2t
together with an other pqrs but pqr1 my be used for qualify root pass (max deposit weld metal 2t) in the case of the thikness >

By cong nguyen (**)

Date 05-15-2008 01:36

Dear friends

I understand your mean, but maybe you misunderstand my question. I ask you about the requirement to combined PQRs, ofcourse I will follow all of variables for PQR in ASME IX when I combine two or more PQRs. Could you please to confirm again my question as below:

- When we are going to combine two PQR, then ASME IX QW-200.4(b) required "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...." Is it mean that the PQR which is going to combine shall be minimum 13 mm thickness. If yes then the thickness is for Deposit or for Base metal thickness?

By cong nguyen (**)

Date 05-19-2008 00:50

How do you think js55?

By js55

Date 05-19-2008 13:54

The idea is to take advantage of the base metal thickness of the second PQR. Who cares what the deposit thickness is of the first PQR, the second PQR, or the WPS since the whole intent of QW-200.4(2)(b) is to combine two PQR's of unequal base metal thickness to support a root pass. If you aren't intending on using the first PQR for a root pass only then you have no need to reference this paragraph. And though I certainly do not speak for the Section IX guys, my opinion is that the idea here is that once you achieve at least a half inch base metal thickness for the first PQR then little is going to change with increasing thickness. This is limited of course by the second sentence of the paragraph making it explicit that this is intended for root passes only.
This root pass only idea, and taking advantage of a thicker qual is the very reason for this paragraph.

By cong nguyen (**)

Date 05-21-2008 04:44

thanks js55

By tom cooper (**)

Date 05-23-2008 16:05 Edited 05-27-2008 12:47

js55-

Coincidentally, I have been studying this same QW-200.4 paragraph for the similar intention of combining PQR's. May I re-ask a similar question in a different way without starting a new thread?

I have a previously qualified weld proceedure, WPS XX, based on PQR XX which qualifies use of GTAW 70S-6 on P1 Group 1, 1/2" thick plate;
I have another previously qualified weld proceedure, WPS YY, based on PQR YY which qualifies SMAW 7018M on P1 Group 1, 5/8" thick plate;
Based on QW-220.4(b) I can now write another weld procedure, WPS ZZ, for a 3/4" thick production joint using GTAW 70S-6 for a single pass root pass (say 3/32" thick) and fill out with SMAW 7018M based on the two PQR's XX & YY and I do NOT need to seperately PQR this combined WPS ZZ.

{edit: Reference to QW-220.4(b) should have read as "QW-200.4(b)" as noted by js55 in a following post.}

Is this true or false?
thankyou.

By js55

Date 05-23-2008 17:30

Tom,
QW-220.4?
Also, as I see it you can do more than what you are asking.
PQR XX allows a 1" thick WPS. And if it was all GTAW a 1" thick deposit.
PQR YY allows a 1 1/4" thick WPS.
So you already have more than your needed 3/4".
Unless I'm reading this wrong.
If you didn't GTAW all the way out on PQR XX you can 2t your deposit, but still go to 1" T.
Write your WPS ZZ and list both PQR's as support. Though you are limited to 1" unless you take advantage of QW-200.4 and root pass only the GTAW, then you can go to 1 1/4".

By tom cooper (**)

Date 05-27-2008 12:43

Thanks JS55-

Just to confirm one small point - The only reason I can do this two process weld, using GTAW for root and SMAW fill is because I have a previous GTAW PQR which produced a 1/2" thick plate. If my original GTAW PQR only produced a 3/8" thick plate, I would NOT be able to take advantage of QW-200.4(b).
IS THIS ACCURATE?

By js55

Date 05-27-2008 14:08

That is my reading of the paragraph, yes.