2 Welders in One Joint to Cover Thickness

you have not mentioned what type of welding it is , is it electric arc welding , organ welding seam welding , gas welding , or mig welding

Seam welding is suitable for thin metal (like food cans) but not 3/4" (20mm) steel.

Organ welding? Can you help us out with this one?

To the OP: I think you are really reaching there, guy. I have not seen this technique described, so I doubt it is acceptable.

For pressure vessels?

<sigh>

For pressure vessels?

What is the applicable code? Where are you at (what country)?

Why do you need two welders? According to this crazy rationale, one welder could do a 60mm-wall pipe joint simply by going around six times. Sorry, not allowed.

NO.

NO. ASME IX QW- 452.1 (b)

can you enlighten QW- 452.1 (b) in details, pls

The welder Qualification (WPQ) is not limited to 12mm of thickness in this process (SMAW) according with ASME IX QW 416. The only restriction comes from the WPS/PQR QW 452.1 (b). In your case you can use one of the welders to weld the 20 mm or both welders, because they are qualificate with no Thickness limit. You have to re check the welders performance (WPQ) and your WPS/PQR.

Agree if welders are qualified based on QW 452.1 (b) as 13mm&over with min. 3 layers, so thickness of weld metal qualified is "maximum to be welded".

But here, their thickness of weld metal qualified limit is upto 12 mm only for each of them(QW 452.1 (b) – thickness of weld metal qualified limit "2t")

Welders following below points as per ASME IX, so please do explain why they not allowed to weld 20 mm production joint? ( 2 welders, each 10mm = 20 mm)

1. Not exceeding their "thickness of weld metal qualified limit" as per QW 452.1 (b) and QW-351

2. Welders essential variables not changed (followed as per QW-350 and QW 416).

3. Base metal thickness limitation is not concerned for welders.

It sounds like you are trying to use your own logic, to try to get around a rule, with some kind of trick that you may see as a loop hole.

You have to take into account the "intent" of the rule. By your logic, you could have 10 different welders that are only qualified to weld 5mm each, each weld on top of the other, and weld a 50mm weld. So you would have a 50mm weld on something enormous and heavy, welded by welders that were only qualified and knowledgable enough to make nothing more than a 5mm weld.

Would you allow your family to live beneath this welded structure?

Already have thought in these ways also.

But looking experts/code users point of view/comments to make clear without any conflictions.

Thanks in advance

I don't think these rationalizations are acceptable.

Dear all

Your comments please.

Based on QW-306, 2 or more welders qualified in single coupon(i.e combination of welders in a single coupon) can weld a production weldment within their limit as per ASME IX.

Why can't weld a same weldment by using welders those qualified individually in single coupons?

References:

QW-306

..."Two or more welders or welding operators,each using the same or a different welding process,

may be qualified in combination in a single test coupon."...

.... A welder or welding operator qualified in combination on a single test coupon is qualified to weld in production using any of his processes individually or in different combinations, provided he welds within his limits of qualification with each specific process.

QW-351

...In any given production weldment, welders may not deposit a thickness greater than that permitted by QW-452 for each welding process in which they are qualified.