Combat Ground Vehicle Welding Code-Steel question

[M249Gunner]

The code states in the footnotes that a groove weld will qualify for Plug welds. One plug weld is a .060" sheet metal piece welded to another component that is appx .250" thick.
The GROOVE weld procedure that I have qualified is .187". This means that my thickness range is half (.093") up to .187". (The mode of x-fer is short circuiting so the max thickness qualified for IS the thickness tested with. With short circuiting mode you don't get the 2x thickness). My question is: Does my groove weld qualification of .187" also qualify my plug weld that has one member up to .250". I am thinking that it doesn't but would like to hear from someone more familiar with this code.
Thanks,
M249Gunner

 

[Duwe6]

Disagree. The 'strength' portion of a Plug Weld is the circular Fillet Weld around the inside rim of the sheet with the holes. The remainder is just 'cosmetic' buttering.

AWS [& ASME] consider any Groove procedure to be acceptable for ALL fillet welds. Per Code, you are OK.

On the other hand, is this welding for a upper-tier MilSpec contractor, or are you subject to direct DCAS audits? If the former, ask their Eng and/or QA dept to approve your WPS for that particular DWG [& joint]. If DCAS might audit you, I'd qualify a thicker groove procedure. DCAS usually isn't very 'sophisticated' and may hold the position that a .187" WPS will not let you weld on .25" material.

 

[M249Gunner]

Thanks Duwe6,
We do have DCMA oversight here. I'm thinking I should go ahead and qualify to a thicker material.

I do have another perplexing question pertaining to this Code (but also to AWS B2.1 "Specification for Welding Procedure and Performance Qualification". It is obvious that the TACOM Code "borrowed" a good deal of it's verbiage from the AWS B2.1 for procedure qualification so therefore I think the intent is the same. So here is the question: For the qualification of a groove weld procedure, the Code(s) state that 2 face bends and 2 root bends are required, along with 2 tensile pulls. What is not clear is which test coupons are required for the Guided Bend testing? Would it be for longitudinal or transverse? If my mat'l thicknesses are .187" and .093", which coupon cut sample would I use to fashion my test plate configuration after? If there is something that clarifies that in either code, I'd really appreciate the information.
Thanks,
M249Gunner

 

[Duwe6]

Coupon could be transverse. Just report that fact on the PQR, 'smile', and act like that is the only possible acceptable manner of testing. When in doubt, pick the best way and declare that to be your company standard.

If you have a written Practice/Procedure for PQR testing, make certain that the above is addressed. That way, you are in full compliance with your QC manual, and DCMA audits will verify that fact.

 

[M249Gunner]

That makes sense. I never really looked at it from that perspective. I may end up approaching it that way. I did start a new thread stating basically the same question as I did here. I've put so much time in digging through 3 Codes, now it's become a challenge! I do like your suggestion and may just go in that direction if someone else can't point me to a clarification.
Thanks a lot for your insight and suggestion!
M249Gunner

 

[gtaw]

The TACOM document is based on AWS D1.1. It includes the concepts of prequalification permitted by AWS D1.1. Even the list of prequalified base metals and the preheat requirements are largely taken from AWS D1.1.

B2.1 has been largely influenced by committee members that have strong ASME tendencies.


Best regards - Al