Summary for single passivation bath Discussion
single passivation bath is the core question here: Karen Gibbs asked whether one Type II nitric/sodium dichromate bath used successfully for 440C, 15-5PH, and 17-4PH could also handle 301, 302, 303, 304, 410, and A286. Anna Berkovich of Russamer Lab said the same bath would probably not work for 410 because it is martensitic, but that the other grades should be fine if the process is already working. A later reply from McHenry, Illinois added that a properly formulated citric-acid passivation process can handle all grades in a single bath, although some grades may need an alkaline pretreatment bath first. The thread therefore presents two practical views: nitric bath compatibility may be limited by 410, while citric acid systems may offer broader one-bath coverage.
July 19, 2013
Q. Hello,
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 utilize the same bath?
Thank you in advance for your help.
Karen Gibbs
– Mount Prospect, Illinois, USA
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.
Blake Kneedler
Feather Hollow Eng. – Stockton, California
July 26, 2013
A. We can suggest the single bath for all stainless steel types.
adv.
Contact me for more information.
Anna Berkovich
Russamer Lab – Pittsburgh, Pennsylvania
(ed. update July, 2025: sorry, Anna has retired)
July 30, 2013
A. Karen,
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.
adv.
Let us know if we can help.
Ray Kremer
Stellar Solutions, Inc.
McHenry, Illinois
July 30, 2013