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STAINLESS : Help with heat-treating and annealing

I am starting to make arms and armor out of stainless steel. These are decorative and real use environments. I need some information on what to use to anneal and heat treat stainless steel without messing making an ugly non-stainless mess. Also what of post heat-treating dips into liquid nitrogen? I have heard some rumors that this does help stainless...?

John Fly
N/A - Columbi, Tennessee, USA
2003

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John-

While unsatisfying, my best answer is "It depends". Are you heat treating martensitic stainless steels, i.e. cutlery grades, to get high hardness at knife edges? Or are you heating up cold worked 300 series sheets to get rid of any ferromagnetic properties?

Generally if you want to take finished stainless steel parts to over 500F, you'll want to use some kind of atmosphere, to avoid discoloration. You also want any 300 series parts to spend a minimal amount of time lingering between 1500 and 800 F, to avoid sensitization. There are a few publications at www.ssina.com that you should read, and the Nickel Development Institute at www.nidi.org also has a lot of information.

There is anecdotal evidence that cryogenic processing will make your brass horns sound sweeter, or make dies last longer. I remain a skeptic, but a simple Google search will get you a number of firms that offer this service.

Lee Gearhart
metallurgist - E. Aurora, New York
2003