Combination of Welding Procedure
Combination of Welding Procedure
(OP)
Hi Everybody,
This is my query:
I would like to prepare single WPS with two supporting PQRs.
PQR-1 is GTAW process with 2.77mm coupon thickness and PQR-2 is SMAW process with 10.00mm coupon thickness. I would like to know if I can make WPS with the PQR-1 as root/hot pass and PQR-2 is fill/cap pass with base metal thickness range 1.5 to 20mm thickness?
The TPI did not agree with this as he said I have to follow ASME IX, QW-200.4(b).
This is my query:
I would like to prepare single WPS with two supporting PQRs.
PQR-1 is GTAW process with 2.77mm coupon thickness and PQR-2 is SMAW process with 10.00mm coupon thickness. I would like to know if I can make WPS with the PQR-1 as root/hot pass and PQR-2 is fill/cap pass with base metal thickness range 1.5 to 20mm thickness?
The TPI did not agree with this as he said I have to follow ASME IX, QW-200.4(b).





RE: Combination of Welding Procedure
RE: Combination of Welding Procedure
You could have applied the same two processes on a single 3/8 in. plate at the same time (e.g., 1/8 in. GTAW root plus 1/4 in. SMAW fill) and had a single qual record with no issue with QW-200.4(b).
But if you use two different PQRs, QW-200.4(b) is clear. I don't understand why there should be a technical difference either. Sounds like a technicality that needs an update unless there is a some obscure reason for the rule.
RE: Combination of Welding Procedure
RE: Combination of Welding Procedure
The root pass PQR has to be at least 1/2" thick. And may be used on any greater base metal thickness for root deposits.
RE: Combination of Welding Procedure
RE: Combination of Welding Procedure
The apparent contradiction you point out can be resolved, I believe, by considering the thickness ranges provided in QW451.1.
There we find that a PQR qualified on 5/8" thick plate covers a WPS from 3/16" thru 1 1/4". If one, then combines this PQR with another which was qualified on 1/8" thick plate, the resulting qualified thickness range would be 1/16" thru 1 1/4".
Of course all essential variables and supplementary essential variables if applicable, must be maintained.
RE: Combination of Welding Procedure
RE: Combination of Welding Procedure
RE: Combination of Welding Procedure
According to ASMEIX...To prepare single WPS with multiple PQRs, refer to QW-451.1, Note (2) "For combination of welding procedure, see QW-200.4".
Where in QW-200.4(a) for qualification of WPS for root pass deposit only, refer to QW-200.4(b).
In QW-200.4(b) to support the single WPS, PQR#1 is at least 1/2" and PQR#2 is the same or greater thickness of base metal..then PQR#1 may be used to deposit the root layers...
The paragraph above contradict with QW-200.2(f) example, since the PQR with base metal 1/2" qualifies the thickness range 3/16" to 2T..I think ASME committee should to review again this standard or maybe my understanding is wrong..
RE: Combination of Welding Procedure
RE: Combination of Welding Procedure
If I can only convince TPI that paragraph QW-200.4(b) shall not be considered, I will be happy. But the code must be followed for combination of welding procedure..as per the requirement according to QW-451.1.
RE: Combination of Welding Procedure
IX-92-75
Q: When writing multi-process welding procedures per
QW 200.4(a), where the tube wall thickness is less than 1 in., using a separate qualification for the root deposit only, must the root deposit qualification coupon be 1/2 in. minimum thickness as stated in QW 200.4(b)?
A: No
What wasn't asked is, 'Must the test coupon thickness for the root deposit only, cover the base thickness of the joint to be welded per the rules in QW 451. ( 2T )
I'm guessing the answer would be - yes.
RE: Combination of Welding Procedure
weldtek,
I would say no. "...in thickness on base metal of the maximum thickness qualifed by the other PQRs..."
RE: Combination of Welding Procedure
Please expand on your logic or enlighten me as to what your quoting from.
Thanks,
RE: Combination of Welding Procedure
RE: Combination of Welding Procedure
That IX-92-75 interpretation really has me scratching my head. Any idea why the response was "No" ?
RE: Combination of Welding Procedure
If you have a PQR for say GTAW on 1/2" thick base metal and a SAW procedure on 1.5" thick base metal. Under certain conditions, you can use this combo to weld 8" thick material using GTAW for the root pass.
Looking at a different scenario, per the interpretation,
if you have a PQR using GTAW on 3/8" thick material and an SAW procedure on 1" thick material under certain conditions you could use this combo to weld 3/4" thick material using GTAW for the root. Of course you could also use GTAW for the entire joint thickness in this case.
RE: Combination of Welding Procedure
My twist on it......
What if this were the question ... by adding the word "alternative" after "separate" and referencing QW-200.4(b)......such as like this.....
Q: When writing multi-process welding procedures per QW 200.4(a),
where the tube wall thickness is less than 1 in.,and using the separate
alternative qualification of QW-200.4(b) for the root deposit only,
must the root deposit qualification coupon be 1/2 in. minimum thickness
as stated in QW 200.4(b)?
A: Yes