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Sheet metal heat warping

MC Parts Kid

Aluminum
Joined
Aug 27, 2014
Location
Hoboken NJ
Top of the day people, Got a major problem and I need help. Got twenty of these boxes we did. The corners are soldered. From us spot welding the bands around the boxes we managed warp the sheet metal (See pictures). I’m hoping that one of you has a solution that was handed down to you long ago. The boxes are made of everyday carbon steel .030 sheet. All of you have a great holiday, Bob, Bean and Baby hound dog
 

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The welds shrink when they cool, the surrounding metal can not so it distorts. It looks like the big stud and the heavy bracket opposite the stud are the problem not the spot welded strip. Better pics?
 
Stretch the shrunken areas. Some easy, some not so.

Spot welds easy to stretch slightly. Could straighten the edges by shrinking them slightly, too.
 
I'm amazed that warpage happened from regular spot welding. We've done lots of spot welding on 20Ga (.036") and even 22 and 24Ga and not seen that. It looks from the pictures more like the boxes got mechanically squashed while welding perhaps. It looks like the open end of the box has been squashed in from the two sides with spot welding, warping the other two sides.
 
It looks like the big stud and the heavy bracket opposite the stud are the problem not the spot welded strip.

I'm amazed that warpage happened from regular spot welding. We've done lots of spot welding on 20Ga (.036") and even 22 and 24Ga and not seen that. It looks from the pictures more like the boxes got mechanically squashed while welding perhaps. It looks like the open end of the box has been squashed in from the two sides with spot welding, warping the other two sides.

Pretty sure the spot welds are not the problem here, go back and look at the pics to see what is welded on the two sides that actually did warp.
 
It does appear to me also that the heavy bracket and stud are where the warpage is occurring. It will be hard to join those two heavy components in the middle of that sheet without any warpage. It is not in focus in the picture, but it looks to me like there is way more weld than necessary holding that stud on from the inside. That stud in the middle of the sheet won't benefit from being fully welded as it is only as strong the .030 it is attached to, so I would say cut down in those areas if applicable.

1) What are you using to weld the components on that are not spot welded?
2) Does it get fixtured in anything that will heatsink, or are you just welding it all together sitting open on the bench?
 
Warpage from welding

It does appear to me also that the heavy bracket and stud are where the warpage is occurring. It will be hard to join those two heavy components in the middle of that sheet without any warpage. It is not in focus in the picture, but it looks to me like there is way more weld than necessary holding that stud on from the inside. That stud in the middle of the sheet won't benefit from being fully welded as it is only as strong the .030 it is attached to, so I would say cut down in those areas if applicable.

1) What are you using to weld the components on that are not spot welded?
2) Does it get fixtured in anything that will heatsink, or are you just welding it all together sitting open on the bench?

The only thing I can think of is the temper of the sheet metal. There is a lot of trashy sheet products out there in the marketplace. When purchasing sheet steel be sure to specify #4 temper for general work. I had a similar problem with spot welded panels. Your spot welds look good.

Roger
 








 
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