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Passivation of nitrided stainless steel
I work for a manufacturer of pistons ring. In order to avoid microwelding, we're trying a nitric acid solutions, which showed good results for 304 and 306 steels, but catastrophic results on nitrided rings. I would like to know if anyone can recommend a different bath for that case.
Walter Serer Junior
Mahle - Sao Paulo, SP Brasil
Hello Walter!
Once stainless steels are nitrided, they lose their corrosion resistance. The nitrogen combines with the chromium in the matrix of the stainless steel, so that it can't form the chromium oxide surface layer that makes stainless steel corrosion resistant. Therefore they should not be passivated, and you should expect them to rust in a corrosive environment.
Lee Gearhart
metallurgist - E. Aurora, New York
Could someone comment on whether Nitriding provides any corrosive protection to 4142 steel?
Jen Irvine
- Corvallis, OR, USA
April 30, 2009
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