The authoritative public forum
  for Metal Finishing since 1989
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Stainless Steel Corrosion & Discoloration

2002

I have a 316 SS tank tank that was blackened by a low pH DDBSA (Dodecyl Benzene Sulfonic Acid) that I would like to bring back to its natural color. What's the best way to do this?

Also, how much harm does 25% NaOH liquid do to a 304 SS tank if stored (hauled) for short periods of time like 24 hours?

D.E. Henson
- Dalton, Georgia

Electropolishing might be your answer. Being that it is metal removal process, it will remove the surface staining.

Chadwick J. Murray
- Bradford, Pennsylvania
2002

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Electropolishing will restore the surface if it is possible to do that to the tank. You should also be able to restore it with a soak in warm citric acid solutions that we can help you with. NaOH will not harm 304 stainless steel for 24 hour periods. Soaking it in NaOH prior to repassivation may be of assistance in getting the finish back to normal.

Lee Kremer
Stellar Solutions, Inc.

McHenry, Illinois

2002