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Cleaning stainless after production

We are producing stainless a2 and a4 bracket, bolt and through bolt. We are facing problem during cleaning of product after production. Firstly stainless bolts are not coming shiny and it is coming like black color. Can you offer any chemical to this problem. Next problem is for bracket some brown colors are coming like corrosion. We tested raw material it is 100% s/s 304 and 316 grade. Can you offer us acid for both purposes?

Best regards,

Ercument Unal
metals - Jeddah, Saudi Arabia

Ercument:

There are a lot of possibilities here, but it sounds like you are putting a lot of iron and/or other impurities on the surface of the 304/316ss parts that needs to be removed. The colors you are describing do not make sense unless you are heat treating these parts after processing. Is this the case? What kind of cleaner are you using to clean them that is producing the black color? You probably need to remove this by pickling and/or passivation of the parts.

If you give us more information about the process, I am sure someone online here can help you.

Lee Kremer
Stellar Solutions, Inc.

McHenry, Illinois

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