Combination of Welding Procedure

[carlomaderazo]

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).

 

[stanweld]

Per ASME IX, you cannot qualify the thickness range stated with the 2 PQRs as stated.

 

[Metalmeister]

Yours is an interesting question that highlights why the code needs interpretation and updates.

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.

 

[DVWE]

I don't see why you cannot do this. What issue did your TPI have with this?

 

[DVWE]

Actually now I see the issue. Sorry, the metric (mm) threw me off a little.

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.

 

[carlomaderazo]

I am also little bit confused with the interpretation...why ASME IX provides an example like in par. QW-200.2(f), where mentioned about "a single WPS may cover 1.5 to 32mm if PQRs exist for both the 1.5mm through 5mm and 5mm through 32mm thickness range". How we can satisfy the paragraph mentioned if in QW-200.4(b) requirement is at least 13mm base material?

 

[weldtek]

CARLO,
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.

 

[DVWE]

I think you have a good argument there. I really don't see the issue with your proposal, as long as all the essential variables are covered.

 

[DVWE]

My last post was directed at Carlo.

 

[carlomaderazo]

Hi Weldtek,
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..

 

[QualityAsia]

I think, you don't need to follow QW-200.4(b) because your PQR#1 is less than 13 mm. QW200(f) is enough.

 

[carlomaderazo]

Hi QualityAsia,
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.

 

[weldtek]

I'm not saying the following interpretation completely answers the question posed, but,

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.

 

[DVWE]

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.

weldtek,

I would say no. "...in thickness on base metal of the maximum thickness qualifed by the other PQRs..."

 

[weldtek]

DVWE,
Please expand on your logic or enlighten me as to what your quoting from.

Thanks,

 

[DVWE]

QW-200.4(b)

 

[DVWE]

weldtek,

That IX-92-75 interpretation really has me scratching my head. Any idea why the response was "No" ?

 

[weldtek]

Here's how I read it.
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.

 

[CodeRef]

I agree w/weldteks explanation and I had to read that interpretation multiple times to understand the clear difference between 200.4(a) and 200.4(b).

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