here is an aluminum part that has had a welded on part ripped off it. I don't know if you can tell by this picture but most of the bead has remained in tact. To me this means it was a cold weld. Am I right?
The bead will be the strongest part for a couple of reasons. First, the filler material is usually of a higher grade than the base metal. Second, the bead on welded sheet aluminum will most likely have a thicker cross section. It's difficult to tell by the picture, but is seems like the part broke off as a result of stress. Is this a part you welded, or is it OEM?
I'm not much of a welder and I can't see the picture well on this small computer screen so I can't really comment on your particular situation, but I did learn one thing about welding aluminum that's helped me. It's pretty much what hemi43 said. The most common grade of aluminum is 6061 and unlike steel it won't fuse together very well. It's the filler rod that gives the weld strength. So if you weld 6061 and use very little filler, or grind the weld down flat, you'll have very little strength.
it's an OEM weld. its a lower control arm mount, welded to the frame. Front impact ripped it off. It just seemed weird that it popped out of there clean without any bending or tearing.
If it's OEM, it's more than likely MIG welding. Also, like a front engine cradle, these were usually made from aluminum extrusions. Most, if not all extrusions are made from a very soft type of aluminum alloy, and the area of the failure just happens to be the weak area. Another possibility is "under-cutting" right beside the weld which would cause the sheet metal to be thinner and would cause a perfect failure point.
not much penetration there, looks like the bead was on the top. i dont do hardly any alum welding but it would appear to be a wire fed weld for certain.
No penatration except the lower left corner. Mig for sure ,seen it even on steel. the angled section on the top left has been cracked fo some time by the grey apearance the small specks of bright material were what was left holding.The way it failed all so fits , sharp inpact and the hole piece snaps off in a lump.Good news ? bad news who knows. if it had held like it should of you would be replacing the section of frame holding it.
