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Single Passivation Bath for Multiple Series of Stainless Steels: 300, 400, and PH series stainless
July 19, 2013
For a Type II bath (20-25% nitric and 2-3 wt% sodium dichromate, 120-130 °F) we run 440C, 15-5PH, and 17-4PH stainless steels. We are looking into adding 301, 302, 303, 304 series as well as 410 and A286 (a PH steel).
From earlier posts, I've been reading that sulfur and manganese content may affect the process, but I haven't been able to find anything regarding the usage of multiple series of materials.
Would there be any problems having all of these materials utlitze the same bath?
Thank you in advance for your help.
- Mount Prospect, Illinois, USA
July 26, 2013
A. No, it probably won't work for 410 because that particular breed is Martensitic. For the others it should be fine to use the same process if it's working for you now.
Feather Hollow Eng. - Stockton, California
July 30, 2013
A. We can suggest the single bath for all stainless steel types.
Contact me for more information.
July 30, 2013
Properly formulated citric acid based passivation is able to handle all grades with a single bath, though for some of those grades you would also need an alkaline pretreatment bath.
Let us know if we can help.
Stellar Solutions, Inc.