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Up Topic American Welding Society Services / Certifications / Essential variable
- - By jrw159 (*****) Date 10-07-2009 23:02
OK, there is a WPS that uses 80/20 shielding gas mix. We want to change to 90/10. This is an essential variable thus requiring re qualification. We run the test plates and they pass resulting in a new WPS.

We have welders qualified to the 80/20 WPS.

Do they now need to qualify to the new WPS or are the WQTR's from the 80/20 valid for the new 90/10 WPS??

jrw159
Parent - - By waccobird (****) Date 10-08-2009 00:15
Welders are qualified to weld a process, material range (classification and thickness), and position.
They qualify by being able to weld conforming to a wps not necessarily the new one.
I'd say they are qualified. unless there appears an inability to produce sound weld.
Hope this Helps more than hurts.
Parent - - By jrw159 (*****) Date 10-08-2009 00:43
Welders are qualified to weld to a procedure that utilizes a process, material range (classification and thickness) and position.

They indeed qualify by being able to weld in conformance to a WPS (welding PROCEDURE specification) and like you say they conform to that WPS that they tested to and not necessarily to the new one. Thus since the new one is not the same as the original, which is evident by the essential variables that require re qualification, wouldn't one have to qualify the welders to this NEW WPS??

If not, why have the essential variables to begin with?

jrw159
Parent - - By ssbn727 (*****) Date 10-08-2009 02:06 Edited 10-08-2009 02:19
Hi John!

I don't have D1.1 2008 on hand but, in the 2002 edition i do remember that 4.7 Essential Variables:

Changes  beyond the limitations of PQR essential variables for the SMAW, SAW, GMAW, GTAW, and FCAW processes shown in table 4.5 and table 4.6 (Which is underlined to referring that if the PQR required CVN Testing then table 4.6 was applicable instead of Table 4.5) when CVN testing is specified, shall require requalification of the WPS (See 4.1.1.3) which only refers to CVN Requirements so if you had to perform CVN testing then, this would be applicable to you: 4.1.1.3 CVN Test Requirements.

When required by contract drawings or specifications, CVN test shall be included in the WPS qualification (I know you didn't mention CVN testing but, I'm including this clause for educational purposes). The CVN tests, requirements, and procedure shall be in conformance with the provisions of Annex III, or as specified in the contract documents.

So, if the WPS didn't have CVN requirements, then we could go to table 4.5 which says in the section for Shielding Gas:

19) A change in shielding gas from a single gas to any other single gas or mixture of gas, or in the specified nominal percentage composition of a gas mixture, or to no gas. And if you go across that line 19), you will see under the GMAW & FCAW processes that there is an "X" in the corresponding box which tells you whether or not the PQR Essential Variables Changes Require WPS Requalification and in your case you did just that... Provided that you also checked line 21) "A change in shielding gas not covered in:" Which is referring to A5.18, or A5.28 in GMAW and A5.20, or A5.29 for FCAW

So now you want to know if the welders are required to requalify to the newly requalified WPS due to the change in the composition of the shielding gas from an 80/20 mix ratio to a 90/10 mix ratio of Argon/CO2...

Well, according to 4.22 "Essential Variables" in Part C Performance Qualification it states: "Changes beyond the limitation of essential variables for welders, welding operators, or tack welders shown in table 4.11 shall require requalification."

Okay then, let's go to table 4.11: It shows me eight Essential Variable Changes to WPQR Requiring Requalification. So I go down the list and, line 1) isn't applicable since you didn't change the process from the original WPS... Line 2) Isn't applicable because you're not using the SMAW process... Then I read line 3) which states: "To an electrode and shielding medium combination not approved by an AWS A5 document." So, that tells me that you need to check with the A5.18, or A5.28 for GMAW, and A5.20, or A5.29 for FCAW as referenced in Table 4.5 in item number 21 (A change to a shielding gas not covered in:) found in page 135 in the D1.1 2002 code. (I don't remember where it is referenced in the 2008 version)

So I go down the rest of the lines, and find nothing else that may relate to your situation which to me means that only line 3) could be applicable and a reason to requalify the welders provided that the shielding gas mix is NOT approved in A5.18, or in A5.28 for GMAW and A5.20, or A5.29 for FCAW.

So unless the shielding gas is not covered in A5.18, or A5.28(GMAW), and A5.20, or A5.29(FCAW), line 3) in table 4.11 does not apply to your situation but, if it does then requalification is required according to Table 4.11. So, if this is the same in AWS D1.1, D1.1M 2008 then, like I said before unless the gas mix is NOT approved in AWS A5.18, or A5.28(GMAW) and, A5.20, or A5.29(FCAW) the requirement for requalification of the welders is NOT necessary... Clear as mud John !!! :) :) :) Hopefully this will lead you in the right direction. :)

Respectfully,
Henry
Parent - - By jrw159 (*****) Date 10-08-2009 02:20
BINGO!!! There it is.

4.22 "Essential Variables" in Part C Performance Qualification it states: "Changes beyond the limitation of essential variables for welders, welding operators, or tack welders shown in table 4.11 shall require re qualification."

That is the link I was missing.

Thanks Henry. :-)

jrw159
Parent - - By ssbn727 (*****) Date 10-08-2009 02:27 Edited 10-08-2009 02:39
So John,

What does it say in AWS D1.1 2008, or whatever version of D1.1 you are working to just out of curiosity? Also, is the gas mix approved to any one of the A5 documents listed in table 4.5, line 21) and, referred to in table 4.11, line 3?

Respectfully,
Henry
Parent - - By jrw159 (*****) Date 10-08-2009 02:34
Henry,
  I do not have it in hand, it is at work. But as far as I can recollect it states as you posted. I just missed the part that I copied from your post in bold. I will check in the morning and verify but I believe you have it word for word as well as shown the direct link between the two.

I am glad it was not a snake. :-)

jrw159
Parent - By ssbn727 (*****) Date 10-08-2009 02:41
Yeah I read ya loud and clear!!! ;) ;) ;) However, if you cook them snakes just right, the meat kind of tastes like chicken!!! ;) :) :)

Respectfully,
Henry
Parent - By waccobird (****) Date 10-08-2009 11:37
Henry thank you again for the input. 2008 changes a bit in that the table is now Table 4.12 and there are only 7 lines, they eliminated line 3 concerning changing to an electrode and shielding medium combination not approved by an AWS A5 document.
I was glad to see that change in that, my opinion has always been the Welder is qualified as to their ability to follow a WPS and produce sound weld. The WPS is the part of the equation that insures the materials involved combine to produce sound weld. Just My opinion.
Parent - - By ctacker (****) Date 10-08-2009 00:23
all the codes I am familiar with they would not need to requalify, unless your changing the process  too!
Parent - - By jrw159 (*****) Date 10-08-2009 00:52
Let me throw this out there.

AISC or IAS comes in for an audit. They pull the WQTR's and the WPS. The WPS# on the WQTR's shows a procedure that utilizes a different shielding gas mixture ratio than that used during production. This ratio exceeds the essential variable limits for your WPS.

Are your welders qualified??

jrw159
Parent - - By Lawrence (*****) Date 10-08-2009 02:00
JRW

You bet.

As a matter of fact.. As far as D1.1 is conserned...  A welder who qualified with gas shielded FCAW is technically qualified to do production with self shielded FCAW as long as the position, material and thickness all fall within the scope of his qualifcation.

The essencial variable (gas) is for procedures rather than welder qualification.

The senerio you note does not say if the production welders using a different gas mix have been provided a WPS.

If a production WPS handed to the welder is out of compliance with the PQR that is hardly the welders fault..  The managment is out of compliance, and so is the product.. The welder is however qualified as long as material, position, thickness are in line with what ever qualifications they hold.. (gas not being essencial here)
Parent - - By jrw159 (*****) Date 10-08-2009 02:27
Lawrence,
  I see it now. I just missed the link and was set off track.

As for the welders themselves it is not an issue. Mixture and filler are controlled and monitored and they are with the program. It is just about the red tape, documentation, and yes and no's of the situation.

I learned alot in a short amount of time once again!! :-)

Take care,
jrw159
Parent - By eekpod (****) Date 10-08-2009 12:45
But aren't all these WPS's pre-qualified anyway?

If so, isn't it just a matter of re-writing the new pre-qualified WPS with the new shielding gas combination, then the welders are now in complience with the WPS?
Chris
Parent - - By jrw159 (*****) Date 10-08-2009 23:18
OK so the way I am seeing this is that we will still have to qualify the new procedure but as long as the new procedure does not infringe upon the essential variables that apply to welder qualification no retesting of the welders is necessary. 

jrw159
Parent - - By ctacker (****) Date 10-08-2009 23:58
looks like you got 20-20 vision now! :)
I don't think you ever gave the code your working to.
and materials etc! As someone mentioned, could this fall under prequalified
Parent - - By jrw159 (*****) Date 10-09-2009 00:06
GMAW-S ??
Parent - - By ssbn727 (*****) Date 10-09-2009 01:27
Well then you can throw the potentially "prequalified" status in the garbage can and count it as a swiiishhh - TWO POINTS!!! Ahhhh wait a minute... Goaltending!!! :) :) ;)

Just curious John... Which year version of the D1.1 code are you working to???

Respectfully,
Henry
Parent - By jrw159 (*****) Date 10-09-2009 11:34
2008
Up Topic American Welding Society Services / Certifications / Essential variable

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