Why does stainless steel get rusty?!
Question:
Why does stainless steel get rusty?
I thought it was STAINLESS STEEL! I have stainless steel can openers & spatulas that are rusty. What's up with that?
& did you know that braces on people's teeth are made of stainless steel? That's why they call people metal-mouth. I used to have braces.
Answers:
Stainless steel is manufactured in a variety of different alloys.
The percent of Chrome and other metals determine which alloy of stainless is produced. Not all versions of stainless is rust proof, just rust resistant.
Not knowing which version of stainless steel you are discussing makes an exact answer difficult. Most stainless steel needs also be exposed to oxygen to retain it's 'stainless' properties. There are also version of steel, Monel and Inconel, that most would consider 'stainless'. Salt water will rapidly affect most versions of stainless with what is called "cloride stress corrosion" which cause a failure of the lattice structure of the metal.
Generally, some stainless steel with a lower chrome content may appear to have discoloration that appears to be rust.