flame straightening of 304 ss

[anjuan]

Hello,
I need to heat a 304 ss L channel, that was warped due to welding, so that it could be straightened. I am not worried about the issue of carbides formation (intergranular corrosion) as much as sigma phase transformation. The heating temperature will be greater than 800 degrees C (the channel will glow red!) for about 15 minutes. Do you think sigma will occur? Thanks.

 

[unclesyd]

Your procedure could get you in trouble. You easily tear the metal at the temperature you are proposing.
Check around and see if you can find someone familiar with straightening SS with a torch and water hose or a few weld placed weld beads.
I personally can move SS all over the place with a torch and hose, only if it hasn't been welded on. If its been welded on such as roll or pipe it takes a little experimentation and still the results aren't guaranteed.