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Up Topic American Welding Society Services / Technical Standards & Publications / D1.1 - Welders qauls w/ backing/backgouging
- - By rickc (**) Date 01-08-2008 20:27
Qualifying any CJP joint qualifies all prequalified CJP, PJP and Fillet joints by Table 4.5 #31 and Table 4.1 #d . Table 4.5 #34 on Page 140 of D1.1:2006 states that the omission, but not inclusion, of backing or backgouging requires requalification of a WPS. Table 4.12 #6 states that the welder can not omission of backing requires personnel requalification.

I am safe to interpret this such that for the most efficient coupon utilization my welders should run a coupon w/ backgouging? The procedure and the welder are then both qualified for backgouging and with backing but not absent either one? Would it be better to invent a CJP joint that uses neither so, that both are qualified for backing, backgouging and without? There's a prequalified CJP joint, B-L1-S, on page 101 w/o backing or backgouging FWIW.
Parent - - By swnorris (****) Date 01-08-2008 21:26
The B-L1-S is limited to the sub arc process with a thickness not to exceed 3/8".  Unless you're qualifying welders with SAW, B-L1-S won't help you.
Parent - By rickc (**) Date 01-08-2008 23:16
Yep, I was merely referencing B-L1-S to show that a single prequalified CJP joint w/o backing or backgouging exists - mostly because I was surprised that there was one.
Parent - - By Lawrence (*****) Date 01-08-2008 23:11
It reads this way because butt joints with open roots are more difficult to join....  (No open roots are pre-qualified per D1.1)

With a backing strip... Or back gouged may be both pre qualified...  The real question here would be "what are your production welders going to do most of the time?"

If they do a bunch of back gouging... It might make sense to test them with back gouging...  That is if your doing your testing in house. 

If they are mostly doing tee and lap joints,  than a fillet test or a groove with backing is more economical...  If you never back gouge there is no need to include it in your welder performance qualification testing in my opinion.
Parent - - By rickc (**) Date 01-08-2008 23:23
Thus far the welders have been qualifying CJP's w/ backing and we were talking about kicking it up a notch as Emeril would say.
Parent - - By Lawrence (*****) Date 01-08-2008 23:41 Edited 01-08-2008 23:44
If the welders are qualifying groove welds in all positions with backing, thats a pretty high bar... 

Like I said... If you do back gouging in production.. than it is reasonable to use it in performance quals too.

None the less... gouging or with backing is equal per D1.1 as far as "how high the bar is"

Open roots raises the bar... But if your not doing open root welding than it's really a waste of time to require it in my opinion.

Why do you want to "kick it up a notch"?....  I think thats the real question that needs to be answered here before you can recieve any quality advice...  
Parent - - By rickc (**) Date 01-08-2008 23:56
"gouging or with backing is equal per D1.1 as far as 'how high the bar is'"

That was pretty much my take on it - except backing vs back gouging for welder quals by Table 4.12 #6.
As for why, it's to be satisfied that I'm casting the widest possible net with our qualifications($) and our welders seem to enjoy doing something different every once in awhile and, as long as they pass, it's all the same to me. Basically, it's a since we're running another coupon anyway thing.

Thank you!
Parent - - By 803056 (*****) Date 01-09-2008 03:38 Edited 01-09-2008 03:43
Just thought I would stir the water and mix up the muddy bottom a little by adding my take on this issue.

The last sentence of paragraph 4.23 (AWS D1.1-2006) dealing with performance qualification says, "Note that qualification on joints with backing qualifies for production joints that are back gouged and welded from the second side."

What it does not say is that a welder qualified with back gouging (instead of backing) is qualified for production welds with backing.

Table 4.12 lists "omission of backing" as an essential variable. It doesn't say "omission of backing or back gouging".

Thinking hard and long, it is not uncommon for welders to fail the performance test because the backing is not completely fused or there is incomplete fusion along the edges of the root to the backing. Back gouging gives the welder a "second chance" to correct any unacceptable conditions in the root. It would stand to reason that a welder that passes the test using back gouging may not have the skills needed to properly fuse the backing bar in production.

The way I read paragraph 4.23 and Table 4.12 (6) is that a welder that back gouges the root of the test coupon is not qualified to weld production welds with backing.

Wouldn't this would be a great question to add to the CWI D1.1 open book examination?

Best regards - Al
Parent - By webbcity (***) Date 01-09-2008 09:36
al , very good , i haven't had my d1 handy lately to go thru these responses , but that is a good question . also please keep up all the good things you do on the forum . i try to read all of them . good luck . willie
Parent - - By Kyle Thoren Date 01-11-2008 17:07
Attended a D1.1-06 code compliance 8 hour course at Fabtech in Chicago this past Fall and the AWS instructor said just the opposite to us.  All our welders are certified using 1" plate, 2G, with backing.  He indicated to us that our guys are NOT certified to weld unlimited without backing.
Parent - - By rickc (**) Date 01-11-2008 17:47
Hmmm, now I'm more confused...
Table 4.12 (Page 150) reads that a welder qualified with backing can only weld with backing on that qualification. Section 4.23 (Page 129) reads that welders that qaulified with backing are also qualified to backgouge. There seems to be some contradiction here.

Am I missing the significance of the "If used in the WPQR test" statement in Table 4.12? Is the welder qualification generated while running a PQR w/ backing more restrictive than running a simple welder qualification? That seems odd to me.
Parent - - By David Lee (*) Date 01-11-2008 18:44
Look's to me like the code is stating qualification's with backing or backgouging will need to be requalified with the omission of backing / backgouging. So I dont see where qualifidation with backing is also qualification without.
Take pipe for instance where you can not use backing / backgouging.
Parent - - By eekpod (****) Date 01-11-2008 18:58
I would agree with Al, that a welder who takes a welder performance qualification test with backing is allowed to backgouge.  But if a welder takes a test w/out a backing bar and backgouges the coupon he/she wouldn't be certified to weld with a backing because of the essential variable.  I don't have my code book here but that does sound familier.
Also I have had many a welder off the street fail because of slag/ lack of fusion in the root on a backing bar test.  If they were allowed to backgouge the test, that would be removed during that step and they would most likely pass the test.
I believe it is harder to pass a test w/ backing than a test w/out backing and backgouged.
Chris
Parent - By rickc (**) Date 01-11-2008 19:47
This makes logical sense to me and Section 4.23 clearly agrees with you but, still seem to contradict Table 4.12:

Table 4.12 Welding Personnel performance Variable Changes Requiring Requalification
(6) The omission of backing (if used in the WPQR test)

It seems pretty clear from this table that if you qualified with backing then you're only allowed to weld with backing. How do you argue against Table 4.12 with an Inspector? Sure Section 4.23 is on your side but, there's a short, simple statement for an inspector to reference and reject your welder qualifications with. It's hard to argue that it's an error in the code when they reference it again ("Backing (YES or NO)") in the Sample Welder Qualification Test Record in Annex N (Page 345).
Parent - - By 803056 (*****) Date 01-11-2008 19:47 Edited 01-11-2008 20:09
I believe there may be a misunderstanding of the term "backing" in this instance. The misunderstanding is that for production purposes (not welder qualification) backing can be a separate material, such as a backing bar or ring, it can be permanent or removable such as is the case with a copper backing bar or ceramic backing, or it can be the base metal itself as in the case of a partial joint penetration groove weld or a double sided groove weld be it complete joint penetration or partial joint penetration.

The act of back gouging a double sided groove weld removes base metal to the depth required to obtain sound metal, usually the root of the weld deposited from the first side. The metal excavated is considered to be "backing" for the weld deposited from the first side.

So, the discussion by the instructor at FabTech is not at all out of line with what has been discussed in my response. I hope I understood your consternation and that I provided some additional useful information.

Welder qualification is not the same as qualifying the welding procedure and yes, the ranges for which the welder is qualified are different than the ranges for which the WPS is qualified when the welder is qualified by the act of welding the test plate used to qualify the WPS.

As I understand it, it boils down to the following:

- Welder is qualified with a backing bar - he is qualified for fillets, PJP, and CJP grooves made with backing or back gouged and welded from the second side
- Welder is qualified with back gouging - he is qualified for fillet welds, PJP, and CJP grooves that include back gouging and welding from the second side. He is not qualified for CJP groove that require the use of a backing bar or CJP grooves without back gouging (as in pipe joints).
- Welder is qualified without backing, i.e., the test consist of a CJP groove welded from one side without back gouging (as in a pipe weld) - the welder is qualified to deposit fillet welds, PJP grooves, CJP grooves with backing, CJP grooves that are back gouged and welded from the second side, and CJP grooves deposited from one side without backing or back gouged. 
- Welder is qualified with a fillet weld - he is only qualified for fillet welds.
- Job specific joint details, i.e., non-standard welder performance tests, devised by the contractor are joint and condition specific. For instance, a manufacturer that is making outside corner joints that must be ground and finished to meet specific customer driven requirements can have the welder weld up a "sample" corner joint as a workmanship sample.  The welder may be required to weld a sample and grind and finish the outside corner to demonstrate the ability to meet specific customer driven acceptance requirements. That test, or workmanship sample, is for that specific joint detail and does not extend to other details.

Remember this questions was specific to D1.1 and may not apply to other welding standards. I hope this helps, but it is only my opinion and my understanding of the question.

Best regards - Al
Parent - - By rickc (**) Date 01-11-2008 20:10 Edited 01-11-2008 20:17
I checked the definition for "backing" in A3.0 hoping that it would allow a broad interpretation of backing but, I'm not sure that it gets me out of Table 4.12 though:

backing. A material or device placed against the back side of the joint adjacent to the joint root, or at both sides of a joint in electroslag and electrogas welding, to support and shield molten weld metal. The material may be partially fused or remain unfused during welding and may be either metal or nonmetal. See Figures 8(d), 12 and 37 (See Figure 4.22 in D1.1 for the general idea conveyed by these figures).

backgouging. The removal of weld metal and base metal from the weld root side of a weld joint to facilitate complete fusion and complete joint penetration upon the subsequent welding from that side.

Everything you've written Al (and others) makes perfect sense to me - I'm just not sure I will always be able to stare down an anal inspector (and I've had some gnarly ones) with mere logic and good sense when they're pointing at a specific sentence in the book. :(
Parent - By David Lee (*) Date 01-12-2008 22:38
Good post in here , but i think that the ? was to qualify his welder's using backing or no.
Simply the answer would be what you use in production. As stated backing can be in many form's even a backing gas.
In any case the production of a complete joint penetration weld is your goal.
Now this may be my own belief but to qualify a procedure with backing will not include a procedure without.
Simply due to the inaccessiblility of the root of the joint in some cases.
On the other hand if you are using a type of backing, the next question is does it stay in place or is it removed?
Read the code you are appyling it to.
Up Topic American Welding Society Services / Technical Standards & Publications / D1.1 - Welders qauls w/ backing/backgouging

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