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Up Topic Welding Industry / Inspection & Qualification / Overlap / Cold-lap vs incomplete fusion
- - By PFI (**) Date 05-08-2019 22:03
All,

We (3 CWI’s) have been discussing Overlap/Coldlap vs incomplete fusion in relation to the AWS D9.1 code.  We see the code does not address overlaps but does address incomplete fusion, if you look in terms and definitions it says overlap is a non standard term used for incomplete fusion (paraphrasing) so does that in fact mean that overlap (incomplete fusion) is in fact reject-able?? 

I have always referred to overlap or cold lap as a form of IF.

Looking for some feedback.

Thank you!
Parent - - By Lawrence (*****) Date 05-09-2019 09:41
Parent - - By PFI (**) Date 05-09-2019 11:55
Good morning Lawrence,

Yeah, I assume that is one of my workers posting the same question.  We had more discussion this morning and resolved to ... "overlap" is not reject-able per AWS D1.9 If the toe of the weld can be seen and verified that the weld does have fusion to the base metal or weld, than its not reject-able for IF BUT if the toe can't been seen, we will reject for IF
Parent - - By jwright650 (*****) Date 05-09-2019 12:48
The picture that was posted in the other forum had the toes visible,  but there was a considerable amount of reinforcement.  Is there an acceptance criteria for excessive reinforcement in D9.1?
Parent - By Lawrence (*****) Date 05-09-2019 13:25
Hi John

Yes there is some language on reinforcement.

8.4 Throat and Convexity of Fillet Welds.
The minimum throat shall be as specified for the application with maximum
convexity not to exceed 1/8 in [3 mm] (see 1.1.3).

1.1.3 This code requires values to be specified by the Engineer for weld type, size, and location of the application. See
subclauses 8.2, 8.4, 13.1, and 13.3.
Parent - - By Lawrence (*****) Date 05-09-2019 13:18
Hi Fred,

Prolly you are right :)

We had a good talk and shared some pictures...  The new forum is a lot easier to drop images into the conversation.

This is what I wrapped up our conversation with:

I think we may be on the same wavelength.

People usually pick D9.1 for a reason.    D9 covers a variety of base metals (or it can)   The procedure qualification and acceptance criteria are comparatively …. um.. less stringent than other specifications that might cover those base metals...

So in your picture above...  You have a nice illustration of overlap that the toe of the weld is visible.   You could shine a light down from the top and it would cast a shadow...  So in D1.1 or D1.6,  D17.1  or D1.2 that might be rejectable...

But for sheet metal under​ D1.9 it would be acceptable....  So you might want to ask yourself... Is a weld with that above profile fit for purpose?  Can it do what the designer planned for it to do?    If it can... I would not die on that hill.

If that profile does not fit the purpose of design...  Than D9.1 may not be the right specification for the project eh?.

Having said all that:

If that "acceptable" overlap is being produced by robots on large batches...  You are wasting a fortune in time and material (as well as risking significant distortion) ...  The excessive reinforcement while not technically ​rejectable is a sign of a process out of control if it is typical.

There are many good reasons to refine that profile even if it might be technically acceptable.
Parent - - By PFI (**) Date 05-09-2019 15:50
Lawrence,

I agree with you completely, I have often rejected the overlap in D1.1, D1.2, D1.6 and D17.1 but D9.1 I have had little experience with.  We are reviewing D1.3 ATM but feel likely we will not have as much leniency as this code is for structural purposes and overlap would present non-negligible risk.
Parent - - By Lawrence (*****) Date 05-09-2019 16:31
Hi Fred,

You will find little comfort in D1.3 in this regard  :)
Parent - By PFI (**) Date 05-09-2019 16:58
Correct, We will likely need to invoke actions above the code to mitigate risk.
Up Topic Welding Industry / Inspection & Qualification / Overlap / Cold-lap vs incomplete fusion

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