Where the
world gathers for metal finishing
Q&As since 1989


-----

Non-salt ferritic nitro carburizing

I have a customer who is looking for an FNC (ferritic nitro carburizing) supplier. They stated that in the past they had samples done in a salt bath that were not satisfactory and that they need to have parts run in a non-salt fluidized bed. Their past problem with the salt bath sounds like a poor rinsing job, since they described the part as having a whitish residue over the surface and in the threads. I have seen cyanide, non-cyanide and gas processes. Is there a non-salt fluidized bed process? If there is, is a part processed in the salt bath harder to rinse making it inferior due to a possibility of salt residue?

Thanks for your time.

William Holland
Metal finishing sales representative - Massillon, Ohio, United States
2004

---

August 22, 2010

Ferritic nitrocarburising can definitely replace salt bath nitriding. Being a gas based process, cleaning issues will be minimal. Also by adjusting the gas ratios, one can engineer the nitrided layer. Post oxidation will further enhance corrosion resistance. FNC with post oxidation & oiling with a water repellant oil will give a salt spray of 200 hrs.

Rahul Gupta
- Pune, Maharashtra, India