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SS304 Forging Rust

Hi, we are an engineering company in Ireland and manufacture goods in China.

We manufacture a forging using AISI304 material. After the casting process the raw part is cleaned with a hydrochloric acid solution to restore the natural colour of the material. We have received some non-conformance reports from our customer that some of the parts are exhibiting rust.

Marco Prinsloo
Product design - Ireland
February 12, 2009

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February 12, 2009

Hi, Marco. HCl will leave the surface highly susceptible to flash rusting. After the HCl treatment, you must apply some sort of rust preventative finish

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

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Ted, AISI304 is stainless steel. While the use of hydrochloric acid is ill-advised on such material, it won't promote flash rusting. I think your post assumes the material to be a plain carbon or low alloy steel which would certainly flash-rust after HCl treatment.

Bill Reynolds [deceased]
consultant metallurgist - Ballarat, Victoria, Australia
We sadly relate the news that Bill passed away on Jan. 29, 2010.
February 13, 2009