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Rusting during water immersion in passivation [Ohio]

July 20, 2010

I HAVE BEEN HAVING TROUBLE WITH PARTS RUSTING DURING THE WATER IMMERSION PROCESS OF PASSIVATION. I CAN'T BLAME IT ON THE MATERIAL DUE TO IT IS A VARIETY, 416, 17-7, 15-5, ANY SUGGESTIONS ON WHERE TO GO FROM HERE I HAVE CHECKED AND RECHECKED AND CAN NOT COME UP WITH A SOLUTION

PAM ALEXANDER
SHOP EMPLOYEE - CLEVELAND, Ohio, USA

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August 26, 2010

When you refer to rusting in the water immersion process, may I assume you mean the water immersion test after passivating?

Since your refer to different alloys, they must be tested separately. If they are combined, you can get selective galvanic corrosion.

Otherwise, any rusting/pitting is an indication that the surface is not passive, which can be due to several causes. Please let us know what type solutions you are using, as well as analytical controls that you have in place.

In general, corrosion of SS indicates iron particles remain on the surface. So what part of your processing either leaves them or restores them?

Mike Burnson
- Chicago, Illinois