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Passivation of Stainless Steel

Passivation of Stainless Steel

Passivation of Stainless Steel

Dear Friends,
While working on passivation, (65% nitric acid bath for 30 minutes), for the stainless steel finished works, i faced the following problem: some of the products changed color and turned to be like dark color on the surface.
If you can help me i would be glaful.
Wissam Khoury.

RE: Passivation of Stainless Steel

What is the SS alloy? Download QQ-P-35C to check whether you are using an appropriate passivation solution for your alloy. Some free machining SS require Type II solution (dichromate + nitric).

Another possible problem is with organics (lube/cutting oil)embedded in the surface as the result of machining. These organics combine with the nitric acid to create a powerful etchant.  For further explanation of this and other passivation problems, see

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