"Corrosion of 301 Spring Tempered Material"

Question:

"We have seen severe attack to a Constant Force Spring made of 301 Spring Tempered SS, when exposed to a Bleach solution (multiple tears). I'm curious if we would see the same sort of effect in a "Salt Water" solution. In other words, is the attack of Stainless Steel by Bleach the same mechanism as that which would be caused by a salt water solution? You mentioned that the bleach is a strong oxidizer, and would cause pitting. But also, seawater might cause pitting. Are these different "types" of attack that lead to similar problems. In other words, I would guess the seawater attack would be galvanic corrosion. Is it correct to assume that that's a different mechanism than the oxidizing that would occur with bleach? Are either of these types of attack "stress corrosion cracking"?"

Answer:

I would anticipate corrosion of 301SS in a bleach solution, depending on the bleach concentration and temperature. Bleaches are strong oxidizing agents and promote pitting of the austenitic stainless steels. I cannot speak to the relative severity of pitting in seawater vs. bleach solutions; however, if seawater velocities are not constantly maintained, it will also pit 301SS. Bleach and seawater are related by their common chlorine atom, which is a known pitting agent of the austenitic stainless steels. Pitting corrosion is a similar mechanism to both bleach and seawater. Pitting is not synonymous with stress corrosion cracking.

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