welding procedure qualification (thickness range) 1

[engineermat]

Hi all,

I have a question on the vendor's welding procedure. ASME IX is used for the welding procedure qualification.

PQR: GTAW + SMAW;
Test coupon thickness: 23.83mm;
Deposited welds thickness: GTAW: 5.0mm; SMAW: 18.83

WPS: GTAW

According to ASME IX QW-403.8 and QW-451.1, the qualified base metal thickness: 5-47.66 mm; the maximum qualified deposited weld metal thickness for GTAW: 10 mm.

However, the vendor insists that the qualified base metal thickness range is 1.5-10 mm. Looks like they use the deposited welding metal thickness for GTAW to qualify the weld metal thickness range.

In this case, can we use 1.5-10 mm as the qualified thickness range?

Actually, a similar question was asked by me half year ago. But I am still not confident to argue with the vendor. Please advise. Thanks a lot.

 

[metengr]

engineermat;
Review Section IX, QW-451. If you use this PQR to support a WPS for GTAW only, the base metal thickness range will only be credited for the GTAW process;

Base metal 1.5-10mm
weld deposit max - 10mm

If you use this PQR to develop a combined process WPS GTAW/SMAW, the base metal thickness range for this combined process procedure would be 5-47.7mm.

Your vendor is correct.

 

[SJones]

Would you walk us through that interpretation as I don't see an allowance in ASME IX to adjust the value of T to the value of t. A "test coupon thickness" is a test coupon thickness. Perhaps it's in some obscure clause or in some interpretation that isn't in the main text yet?

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[metengr]

There is no interpretation, and you don't need one. If the PQR as stated in the OP is used to support only a single WPS for the GTAW process, one cannot take credit for the full base metal thickness range of the coupon for GTAW. Why would you even list a full base metal thickness range for having only one process with a limited deposit thickness??????

Using this PQR to support only a GTAW WPS makes no sense. I would have simply written a combined process WPS that would allow GTAW and SMAW to be deposited for the full thickness range of the coupon qualified with both processes.

 

[DVWE]

I believe it should be like this:

5mm minimum base metal thickness because SJones is correct, T is T.

The maximum base metal thickness CAN be further limited, in this case, 10mm. There's nothing in the code that says you can't further limit something like base metal thickness.

engineermat, is there a need to weld on base metal thicker than 10mm? In my mind, there's no reason to have 47.7mm as your upper limit and a single process which is limited to 10mm. But, if perhaps there's something like a partial pen groove on 47.7mm, and your deposited GTAW is 10mm or less, then I'm inclined to believe you are correct.

 

[metengr]

Sorry folks, I had a typo in my OP, it should be base metal 5mm-10mm thickness range for GTAW, not the 1.5 mm min.

 

[engineermat]

This WPS will be used for F.P. groove. So the qualifid thickness range shall be 5-10mm, as stated by Metengr.

 

[SJones]

Phew! Good job it was a typo. I was sweating a bit there!

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[weldtek]

metengr,
Correct me if I'm mistaken, but, it seems to me that for the case above, per Code rules, the qualified base metal thickness range is 5 - 47.6.
Granted max deposit thickness for the GTAW process is 10, but, base thickness is separate and distinct from deposit thickness. One might use such a WPS to make a repair to base metal or to weld a joint of dissimilar thickness.

 

[zhlin]

I have a similar question and found out this thread.

I am still not clear about the qualified thickness range of base metal.

Per your discussion, the max. qualified thickness of base metal is 10mm, which seems determined per the deposite metal. So why the min. thickness could not be qualified the same manner?

Thanks.

 

[DVWE]

Because the minimum thickness is driven by QW-451. It changes based on the thickness of the coupon.

 

[Ballbearing1]

Hello all,
Posted this on the same subject on the AWS forum a while back.

Hi Marty,
Had a bit of a disagreement with the contractor the other day and hopefully someone on here can clarify please.
PQR submitted for GTAW/SMAW 316 s/s 10.97 mm thick.
GTAW 3.0 mm / SMAW 8.0 mm
Contractor wrote a WPS based on this PQR with only the GTAW portion used and listed base metal thickness as 1.5 to 6 mm as the GTAW portion of the coupon was less than 10 mm (3/8")
However, it is my interpretation that as the test coupon was greater than 10 mm (3/8") the minimum base metal thickness would be 5 mm (3/16") and not 1.5 mm (1/16")
As they were wanting to use it for numerous Sch 10 welds (3.05, 3.40,3.76 mm etc) I felt the WPS was not qualified for those thicknesses.
Am I correct in my interpretation ?
Regards,
BB

 

[DVWE]

BB,

Are you the one that wrote this message?

I believe the interpretation is correct. Coupon T is T.

However, if the code of construction was AWS, then it is different. See Table 4.2 of D1.1.

 

[welding234]

they first reply is correct,
but smaw is qualifed with backing strip or backgaugeing
velan