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Up Topic Welding Industry / Inspection & Qualification / D17.1 - Define this condition, please.
- - By metllab Date 01-22-2016 18:29
Please help me settle an interpretation issue.

So in this fillet cross section the effective thickness of the joint has been reduced to ~ 75% the thickness of the vertical member due to melting on the back side of the plate.  This obviously cannot be good, however, D17.1 and referencing AWS 3.0 does not specifically deal with this type condition.  Many would call it suck-back (though a non-standard term for underfill), however, underfill, technically is limited to groove welds.  Undercut seams to be the most obvious, but once again, the callout only applies to the toe of the weld face, or root, but the location of this indication is not technically at the root of the joint as defined for fillet welds.

I would think one might make an argument that since fusion had occurred completely through the sheet member that the root of the weld in now on the back side of the coupon-making it a form of undercut.  However, when someone wants something to pass, technicalities are usually the first place they look for loopholes.  Any comments would be very welcome.

Thank you

Parent - By pipewelder_1999 (****) Date 01-22-2016 19:16
I have seen this same (or very similar) image and question in the past. Since this seems to be a sample (maybe for qualification)  and not a production part, some investigation is required. I have seen cases of this on Welder Qualifications for test welds however without the thickness being reduced below the base metal thickness.

D17.1 may not have the "support" you need for rejection however if you don't wanna put your name on it and can explain why, just go for it with the understanding that you are of course accountable for your actions. The other option is to place a hold on the item and request guidance from the engineering authority based on the fact that this condition has reduced the effective thickness of the base metal/weld metal below the as supplied thickness.

As an inspector, for all I know, the design "minimum" thickness is 75% of the nominal thickness. Thus the joint MAY be OK however I would request guidance from the engineering authority 1st.

Codes do not always cover all the bases but if all you have is the code and you wanna stick with the code, stick with it.

I probably wasn't much help. Some of these things are best answered internally. Hate to have to back up a questionable decision with "...well the guy I talked to on the internet said .........."

Have a great day

Parent - - By Lawrence (*****) Date 01-22-2016 19:43 Edited 03-11-2016 18:03
The call-out may have been for a fillet.

What you have achieved/shown in your excellent image is a T-Weld with melt-thru (Fig. I-2) That has a noticeable/measurable reduction in t

Since your joint is actually CJP,  I think you can make an argument to inspect it as such and reject for underfill on the "other" side and undercut on the arrow side (unacceptable profile via Fig 6.1 [C].

Fillet or CJP T-Weld is not a stopper here
Table 7.1 uses the terms  "Underfull and/or Concavity"  This is what you can rest on.  They are two different things, and the code is recognizing this.   The back of that weld is concave and measurable.  You have a formula to judge via weld class in the table.
Parent - By pipewelder_1999 (****) Date 01-22-2016 20:52
If its a groove welded Tee joint then yup Table 7.1 applies as far as underfill goes.  Its bad and the code says so. If its designed as a fillet weld, I'd have a hard time providing a code paragraph to provide. Face or Root Underfill is not addressed for fillet welds.  Still wouldn't accept it as a production acceptable condition for a product unless the engineering authority gave me something.
Parent - By TimGary (****) Date 01-22-2016 20:01
I don't have a coy of D17.1 with me, but isn't there a clause in there somewhere for base metal damage (nick, gouges, etc.) beyond 10% material thickness to require rejection / repair?

Parent - By peterj357 (*) Date 01-25-2016 22:04
I would classify this condition as underfill, because, although Table 7.1 in D17.1 says "Face or Root Underfill (Groove welds)", Clause 3 Terms and Definitions defines underfill as " A condition in which the weld face or root surface extends below the adjacent surface of the base metal."  The definition of underfill in D17.1 does not specify the condition applying only to groove welds, so I believe the argument could be made in the case of the supplied picture the root surface of the weld extends below the adjacent surface of the base material, and could be evaluated using the underfill acceptance criteria in Table 7.1
Parent - By MRWeldSoCal (***) Date 01-26-2016 17:52

In these cases --->    I rejected these.  I ran into the same dilemma.  Now if this is to D17.1 CLASS A I would reject based on undercut since its .002 based on full length of weld.  Also as was said before you can make the argument that you are checking a fillet weld which is clearly no longer the joint. It is now a full CJP.  I would send the customer the photo along with your discrepancy and see how they handle it.  You cant judge a fillet when there is not one.  Also I believe the minimum unspecified weld size is 1.5T.  that weld does not look like its more than 1.5T the vertical material.  my 2 cents

J Maxwell
- - By metllab Date 01-22-2016 20:35
Thanks for the responses so far.  This actually is a fillet weld cross section one of our technicians prepared for a welder qualification.  Based on the limits for undercut on Class A welds of 0.07T per the referenced specification, we maintain this is an unacceptable weld.  However, because welder qualification coupons are based on only four different configurations: sheet groove, sheet fillets, tube grooves and tube fillets, and the criteria in table 7.1 pertains to these specific joints only, technically the nomenclature for defects (as defined by AWS D17.1 and AWS 3.0) does not address this specific condition. 

We are not looking to assert a position based soley internet conversation, however, sometimes there is language, paragraphs, annexes, etc. that we may have overlooked that would give us a stronger position for interpretation with our client.  Therefore, the collective thoughts of those in the know is always appreciated.
Parent - By pipewelder_1999 (****) Date 01-22-2016 21:05
I would have a difficult time rejecting a welder qualification test for a FILLET welded sample based upon the criteria in the code only for the condition shown if the undercut on the welded side of the joint did not exceed .07t. The condition on the other side is not undercut as defined by any sources I am aware of.

I think this very condition (which can be difficult to control with some production settings) is why 17.1 allows for some IP at the root for thinner materials with fillet when performing qualification tests.  But that is just a guess.

So suggesting to your client that "cooler parameters" could prevent/minimize this type of condition could be something to minimize this is the future.
Parent - - By Lawrence (*****) Date 01-22-2016 21:14
Mil-STD-1595 used to address this specifically :(
Parent - By pipewelder_1999 (****) Date 01-22-2016 21:22
Not exactly sure why perfectly good Mil Stds are replaced with other documents. I read the forward but still don't get it.
- By 803056 (*****) Date 01-23-2016 00:11
The term "melt-back" comes to mind. I cannot check my books while I'm on the road and with the weather, it might be a while before I do get home. This is the third time I've rebooked and had the flight cancelled.

It isn't just another job, it is an adventure."

Up Topic Welding Industry / Inspection & Qualification / D17.1 - Define this condition, please.

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