Metal finishing Q&As since 1989

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SS industrial butter churner getting rusted

2005

Hi..

I had recently observed that an equipment made of SS 316 material is been used for churning butter , but ironically after few months when they had started making salted butter , I have observed there were dot like rust/corrosion spots in it, some of them were continuous and others were scattered around the shell of that equipment/churner.

I would be grateful if any one of you could kindly take pains to clarify this out of my mind.

Thank you

Tamc
swatch equipments inc. - Colombo, Sri Lanka

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Pitting corrosion of T316 is common in the presence of chloride (salt).

Jeffrey Holmes, CEF
Spartanburg, South Carolina
2005

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I think that only cathodic protection can help you(maybe, or use better SS grade).

Good luck!

Goran Budija
- Cerovski vrh Croatia
2005

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This is not an uncommon problem in salted butter manufacture. We have dealt with this before. The best answer is constant mainenance by re-passivation BEFORE you get the pit corrosion. This works for other companies with 316 ss tanks.

Now that you have the pit corrosion you can remove the rust with a citric acid product, but it will come right back unless you do some electropolishing of the pits to get rid of it all. You can do this with a large wand and the right citric products, or there are other systems around to do the job.

Lee Kremer
Stellar Solutions, Inc.

McHenry, Illinois

2005