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Nitriding in SS 321

2005

Dear Sir,
We use SS 321 material, we make sring lever out of this material
We do nitriding process to this material
Storage time for this finished product is 1 year
Shelf life of the product is 20 years
We are facing the problem of rusting / tarnishing /scale fomation over the surface of the material (nitrided material)
We had done salt spray test for this comp to -it had started rusting
When we had done salt spray test for the base material (SS 321) it was not rusted

Nitriding condition's
LPG Nitriding
Temperature :590 Deg Cel
ammonia ⇦this on eBay or Amazon [affil links] :Liquid
Duration :2hours and 45 minutes

Regards,

Ebenezer
Easun MR India - Vadodara, Gujarat, India

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2005

Yeah, it will do that.

It is the chromium in stainless steel that gives it the corrosion resistance, by forming a tightly adherent chromium oxide layer on the surface. When you nitride a stainless steel, you form chromium nitrides as part of the case layer. This effectively destroys the corrosion resistance.

Here in the States, the Bodycote group of companies has a process for nitriding stainless steel that they claim preserves the corrosion resistance.

Good luck!

Lee Gearhart
metallurgist - E. Aurora, New York