max gap in sheet steel 1

[sfifab]

I had a situation arise in our fabrication department where two galvanized channels are to be welded together using GMAW. Both pieces are .070" thickness, have a radius edge and when joined together produce a flare-v-grove. The parts are about 4' long, this groove runs the entire 4' length and normally, when broke correctly, produce a minimum root gap. Well today we have 50+ pieces that mate fine at the ends but produce an opposite bow in the middle leaving a 1/4" gap in the middle tapering to the ends. I have a quality guy telling our fab dept. to stick 1/16" shims in the gap, weld it up and take the shim back out. I know in my gut sticking shims in a gap so we don't have to scrap 50+ parts is not a good idea but, I can't find any evidence in the customer's spec or AWS D1.3.

Can anyone reference me to a specific clause?

 

[Mr168]

5.3.2 in the 2008 edition: The parts to be joined by welding shall be brought into close contact to facilitate complete fusion between them.

 

[gtaw]

5.3.2 of what welding code?

Best regards - Al

 

[phighfill]

AWS D1.3-98

 

[Mr168]

Correct, D1.3, but I checked the 2008 edition. Should have clarified that in my post.

 

[sfifab]

"close contact"...Well that narrows it down. Since it doesn't define close or give any specific measurements, I guess I will have to find something else to keep these guys from trying something like this.

Thanks

 

[Mr168]

Welcome to the wonderful world of AWS. If you think that's obscure, try building nuclear facilities to their standards...

That aside, you may wish to find out what they're using in the way of welding procedures. The use of prequalified procedures/joint details and their permissible root gaps are more restrictive than those qualified by test for joint configurations other than square grooves. They can be found in figures 3.1A through 3.3D.

 

[sfifab]

LOL...no way, i'll stick with manufacturing. That's a good idea, I know the WPS won't cover that gap and unless they try to make a new one...that might work.

Thank you sirs,

 

[phighfill]

Mr168

What is really obscure is when your quality procedures for inspection are "copy and paste" straight out of AWS.

 

[Mr168]

phighfill - quality procedures are one thing, it's even worse when you see design specifications written for stud welding that are copy/paste from clause 7!

 

[phighfill]

very true