Hi,

I've got a bit of an ongoing saga with a welding shop that are doing some work for us. They've got into a slightly frustrating habit of sending me almost daily variations to their original WPS with no justification of how it still conforms to the PQR, leaving me pawing over ASME IX every morning trying to figure out what's going on.

Anyhow, the latest one has got me stumped: They have a PQR (say PQR 1) for GTAW butt on 22mm wall thickness super duplex (25% Cr) 110mm ID pipe, qualified on 20mm WT. Current range between 70 and 90 A, 11-14 V.

In a bid to speed up the job, they want to combine this with another PQR (say PQR 2) for the same material, 55mm thick, with root and hot pass performed by GTAW and the fill and cap done with SMAW, current range between 90 and 120 A.

As mentioned above, the job is a series of pipe butt welds on 22mm wall thickness super duplex (25% Cr), 110mm ID.

They propose using PQR 1 for the first 10mm (root, HP and some fill) and then taking the root and hot pass from PQR 2 to use as the fill and cap (remaining 12mm). The SMAW part of PQR 2 would not be used.

I can't find anything in QW 200.4 that says explicitly that you can't do it, but nor does it say that you can. It certainly doesn't seem in the spirit of what AMSE are allowing though. It does just hit the 2t limit for deposited weld, but doesn't feel quite right.

Any thoughts that anyone's got as to whether this is permissible would be greatly appreciated.

Roscoff,
With all due respect your post is not making sense.
If they have a 20 mm PQR with GTAW then the 22 mm production joints are no problem - why introduce another PQR ?
The only reason would be if they wanted to use the SMAW portion of PQR 2 but you have stated "The SMAW part of PQR 2 would not be used".
Regards,
Kiwi

Sorry Kiwi, you're quite right about not making sense.

They want to use the increased current and run-rate qualified in the GTAW root portion of PQR 2 to perform the fill and cap of the WPS which is currently based on PQR 1.

Their objective is to be able to up the current to 120 A but still do the complete weld with tig.

Hope this is a little clearer

Regards,

Roscoff

Roscoff,
It is acceptable to write a WPS supported by multiple PQR's, however, in this case it seems that they could generate a WPS covering the range of heat input they feel like they need to use, supported by just the second PQR. An in depth review of the WPS and supporting PQR('s) is necessary and can't be done here with the information presented.

Roscoff,
What is the fabrication code ?
Is impact testing required ?
If impacts are not required amps, volts and travel speed are non-essential variables.
If impacts are required you are governed by not being allowed to increase the heat input. If you increase the amps you may be able to stay below your qualified heat input with increased travel speed.
But as Weldtek has stated without all the information it is very hard to offer advice,
Regards,
Kiwi