Calculate and control distortion stainless steel when being heated

[kakalee1]

Hi all,

I have a piece of stainless steel 63 x 43 inches and 1/16 thick. It has a lot of .06 holes on it, similar to a vacuum table. One face is held down vacuum, and the other face is being heated to 150 C uniformly. After being heated, the heated face is distorted. I would like to find a way to prevent this from happening or at least minimize the effect.

For curiosity, if anyone can give me a reference on how to calculate the distortion amount, that would be greatly appreciated.

All feedback are welcome.

Thanks.

 

[IRstuff]

Distorted how? Is it even repeatable?

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[TVP]

What is the grade/composition of the stainless steel? How was it processed? These will both have a HUGE effect on distortion.

 

[arunmrao]

In my opinion, even without heating , a perforated sheet will distort. It is quite a challenge keeping it flat.

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[berkshire]

khoanamlee (Mechanical)

The distortion amount will depend on the residual stress left in the sheet at manufacture. Since this varies from sheet to sheet, there is virtually no way to calculate it.
A better way would be to flatten the sheet after heat treatment. This can be done with leveling rollers, or stretch leveling.
The stretch leveling method would require you to have an excess amount of material on your sheet, to be trimmed off after the leveling operation is complete.
B.E.

You are judged not by what you know, but by what you can do.

 

[tbuelna]

khoanamlee-

The description in your OP was a bit confusing. You stated that your 1/16" thick stainless steel sheet was perforated with numerous .06" diameter holes, and that the sheet was held down using a vacuum while one one face was heated to 150degC. Since the sheet was perforated, how were you able to hold it down using a vacuum? Did you use something like a vacuum bag sealed around the perimeter of the sheet to hold it down? Was the sheet heated for a long enough period so that it achieved a uniform 150degC throughout the entire part? Under what conditions was the sheet cooled? Did you check the flatness condition of the sheet prior to heating it?

What process was used to produce the holes (drilling, laser, punching)? If the holes were all punched from one side, the punching process could have produced different residual tension/compression stresses on opposing sides of the holes.

 

[berkshire]

khoanamlee (Mechanical)
I think a bit more information is in order here, Are you fabricating this sheet, or are you using the sheet and encountering a problem?
B.E.


You are judged not by what you know, but by what you can do.