Welds Cracking

[burns5702]

We have a weld on a cover that is cracking. I was wondering if anyone had any suggestions. The cover is 11x11.56x12.5 inches 0.090" thick AL 5052-H32. The two sides of the cover are welded onto the middle section with a .12 fillet weld ground down. The covers mount onto a machine that moves at 1g acceleration. There are two fasteners on each side of the cover (M4's) none on the top or bottom. We are seeing cracks along the weld at the tops of the covers. Any ideas ? I have requested, from the vendor, what they are using for a filler metal.

 

[CWIC]

burns5702:
I would request more than the filler metal. I would request to review the welding procedure (WPS) and PQR (test data) if it was qualfied in accordance with AWS D1.2.

 

[metengr]

The recommended filler metal for joining aluminum alloy 5052 is an AWS 5.10 ER5356. You have other alternatives like 5183 and 4043, however for strength the recommended choice is ER5356. Also, for thin gage material the GTAW (TIG)process is preferred.

One additional question - where exactly are the cracks, in the weld deposit or along the edge of the weld?

 

[Carburize]

Is it cracked when it arrives or are the cracks developing in service because of high levels of vibration?

 

[burns5702]

1) The cracks are in the weld deposit. The weld connects the two pieces of AL at 90 degrees - so the two pieces are "ripping" apart.

2) The cracks are developing in service - possibly due to the levels of vibration.

 

[stanweld]

The weld metal is not nearly as strong as the base metal. Have you taken that into account in your design?