Mitered Channel Corner Weld

By Edward Skarlinski Date 05-21-2009 21:08

We are having problems with inspection and certification of a welded box made from channel. I need a cjp weld specification callout for welding this box made from mitered structural channel. The Channel is C4x7.25 (4tall, 1.721flanges, .321 web). The flanges are on the "inside" of the box (flat walled exterior). Currently, the symbols are as follows.
Flange welds: below the reference line is a 3/16 bevel groove with a ground flat contour, above the reference line(inside the box) is a 3/16 fillet weld.
Web welds: below the ref line is a 3/16 bevel with a ground crown contour, above the line(inside)is a 3/16 fillet.
I believe our problem lies in the mitered web.
Any ideas?

By welderbrent (*****)

Date 05-21-2009 22:12

Edward,

First, WELCOME to the AWS Forum. Hope you can get some answers that will be of help for your job.

Second, I'm having some trouble following your description of the weld at the corners.
*If the pieces have been mitered then the inside flange welds should be groove welds in a butt joint, not fillet welds. (Did I miss something?)
*The Outside Flange would be able to be a ground flat groove weld.
*The Outside Web weld should be a corner weld.
*The Inside Web would be the only fillet weld.

1) Should this have coped corners instead of mitered? But there would still be some groove welds as well as fillets.
2) If they are welded from the inside first with parts beveled, then you should be able to back grind into clean metal from the outside and get a cjp weld all around with no problem. Then grind your flanges flat and contour your corner weld.

Did I miss something? Other than some symbols may be wrong, it should not be a difficult operation. But the corners will need careful attention as most people do not grind deep enough when back grinding there to get good weld all the way through. And you are looking for a Complete Joint Penetration Weld.

Maybe I missed something in your question. If so, hopefully someone else can pitch in.

Have a Great Day, Brent

By Edward Skarlinski Date 05-22-2009 17:04

no, you missed nothing, the welds on the print are wrong: I was reporting what I had in hand.
I'd like to call the flange welds a double V & the web weld, from the outside, a V with back back weld & 3/16 fillet on inside.
However, I understand that there might be a problem with the "backgouge" capability.

Thanks,
Ed

By welderbrent (*****)

Date 05-22-2009 23:28

Edward,

The only problem I see is making sure you get it cleaned out deep enough to allow for CJP weld from the second side. It doesn't truly matter which side you weld first if the prints do not specify a first and second. I have just always found it much easier to prep the inside surfaces for welding first, tack the parts together, weld out the inside, then back grind the outside for the second weld.

"Backgouge" is a term that covers grinding, arc gouging, plasma gouging, chipping, scarfing, any procedure which cleans the joint out for welding. The only concern is the quality of the prep.

So, am I understanding what you mean by a "problem" with the backgouge.

Have a Great Day, Brent