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Up Topic Welding Industry / Inspection & Qualification / ASME IX Dissimilar Thickness PQR's
- - By Niekie3 (***) Date 08-17-2003 12:26
Hi Everybody

A number of times, I have come accross the practice of performing a PQR test with different material thicknesses. For example, an 8mm P1 plate welded against a 20mm P1 plate. The organization making this test then claim that it qualifies welding a base metal thickness range of 1.6 - 40mm. Obviously the deposited metal thickness "t" is only 16mm.

I can not find a direct reference to such a situation in ASME IX, but one can argue that it is in some way a combination of a full penetration and partial penetration groove weld.

Are any of you familliar with this approach? Do you believe it is allowed by the code?

Regards
Niekie Jooste
Fabristruct Solutions
Parent - - By Shane Feder (****) Date 08-18-2003 00:28
Niekie,
From what I can see in the code you are correct in what you are saying.
I think it is one of those "loop-holes" that we find from time to time that don't seem to be right but there is no documentation to refute it.
QW 202.4 states " More than one PQR may be required to qualify for some dissimilar thickness combinations" but it gives no more detail.
If the base metal thickness qualified is up to and inclusive of 40mm they can still only weld to 2x Deposited Weld Metal thickness which is 16mm.
What I find really confusing is if a welder uses that WPS for qualification on a 16mm plate then that qualifies him for unlimited thickness ( max to be welded) even though the procedure is only valid to 16mm.
Have you had access to the WPS's that have been prepared using these PQR's and were they acceptable ?
Regards,
Shane
Parent - - By Niekie3 (***) Date 08-19-2003 18:55
Hi Shane

Thanks for the reply. I personally do not have a problem with the welder qualification issue, because even with a WPS qualified from a PQR welding 8mm to 8mm you will have the same situation. The moment the welder has welded over 13mm, he is qualified to an unlimited thickness. Just remember that welder qualification is not directly linked to any WPS.

Just some other bits that may guide us in a direction, but not actually give us an answer:

1) QW-200.4 deals with combinations of welding procedures. In particular it states in part (b) that one can use two different PQR's to set up a WPS where the second has a greater thickness than the first, and that you can weld with the processes on the firsts PQR on the thicker material of the second PQR (up to 2t of the first PQR) as long as the first PQR was tested on a material greater than 13mm.
2) None of the sketches depicting test pieces and specimens seem to make allowance for materials of different thickness.

It appears as though it is not the intention of the code to have groove weld test pieces welded on different material thicknesses, but I see nothing that expressly disallows it. Possibly someone has the interpretations, and this question has been addressed there?

Regards
Niekie Jooste
Fabristruct Solutions
Parent - - By Shane Feder (****) Date 08-19-2003 22:18
Hello Niekie,
I must confess I am a Kiwi working in Australia so I will try not to mention the rugby union.
Some more thoughts on the subject of material thicknesses, please correct me if I am wrong.
A PQR may be used to formulate/prepare numerous WPS's according to requirements and it may also be replicated verbatim to produce a single WPS.
The example you mentioned in your first post was a PQR covering 1.6 mm through 40 mm.This could then presumably be replicated to give you a WPS covering 1.6 mm through 40 mm.
QW 200.2 (f) states " a single WPS may cover a thickness range from 1.6 mm through 32 mm if PQR's exist for both the 1.6 mm through 4.8 mm and 4.8 mm through 32 mm thickness ranges."
This appears to state that to gain coverage from 1.6 mm through 32 mm you would require two (2) PQR's.
Your thoughts ?
Regards,
Shane
Parent - - By Niekie3 (***) Date 08-20-2003 18:59
Hi Shane

I am struggling to write this reply, following your mention of the rugby. I find it difficult to see through my tears! Oh well, while there is life, there is hope. (Not a lot of hope mind you!) At least you guys (The All Blacks) look like the top contenders for the world cup. Let's just hope that one of the Northern hemisphere teams don't "get lucky"!

Your argument is once again an indication that it is not the intention of the code to allow the welding of different thickness base materials in a single PQR test piece. None-the-less, it is not (to my mind at any rate) positive proof that it is disallowed, only an indication of such.

I am sure that this must have been addressed somewhere in an interpretation. If only I had access to the interpretations!

Regards
Niekie Jooste
Fabristruct Solutions
Parent - - By TolgaKantaroglu (*) Date 08-13-2007 07:00
Dear Niekie,

I know this is a very old discussion but I have a similar problem regarding with the QW-200.4. Could you have an access to the interpretation of the subject code section. I have a WPS prepared with a combination of two PQRs root pass is taken from the first PQR GMAW (STT) with deposited thickness 0.220", fill and cap is taken from the other PQR SMAW with deposited thickness 0.636". This WPS has been approved several times by most of the clients however this time one of our client raised a query about the minimum thickness. They say that for a combination of the processes the minimum qualified thickness shall be 13 mm rather than 0.1875" referenced by QW-451.1 as per deposited weld metal thiscknesses. Even though I read QW-200.4 several times I couldn't interpret it, therefore I need a proper interpretation of the code section. If you can help me, I will be thankful.

Best regards,

Tolga Kantaroglu    
Parent - - By js55 (*****) Date 08-13-2007 14:28
Its sounds to me like you are talking about two seperate things. Deposited weld metal thickness and material thickness. There is no minimum for deposited weld metal thickness. And the minimum material thickness would be determined by the thickness of the material you used in your PQR, which you don't clarify, but I am assuming from your deposit thicknesses would put in the regime of 3/16" minimum.
Parent - - By TolgaKantaroglu (*) Date 08-13-2007 14:34
Thank you for your reply but some how I found the subject interpretation and it solved my matter out. I can share it with you if you want to have it.

Regards,

Tolga
Parent - By js55 (*****) Date 08-13-2007 14:56
Certainly.
Parent - - By ssbn727 (*****) Date 08-13-2007 11:40
Hello Niekie!!!

It's sure good to see you back!!!

Respectfully,
Henry
Parent - - By jon20013 (*****) Date 08-13-2007 11:56
lol, Niekie isn't back, the postings are from 4 years ago!!!
Parent - - By ssbn727 (*****) Date 08-13-2007 20:08 Edited 08-13-2007 20:11
I knew I should've been in bed at that hour!!! Must be the new meds I'm on :) I guess it happens to all of us every once in a while... not being able to discern that last, tiny set of numbers on the date :)
Thanks for clearing that up for me jon :)

P.S. I wonder whatever did happen to Niekie because I rather enjoyed his posts and do miss the broad knowledge and technical expertise that he bought to this forum...
I pray that everything is well with him :)

Respectfully,
Henry
Parent - By jon20013 (*****) Date 08-13-2007 20:12
Don't feel bad at all Henry, I did the exact same thing about a year ago!!!  Yep, I was responding to a Nieke posting!!!! ;-)  I wonder what ever happened to him????
Up Topic Welding Industry / Inspection & Qualification / ASME IX Dissimilar Thickness PQR's

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