Originally Posted by redsdad
Rub 304 or 316 with a piece of carbon steel or use tools such as a file which has been used previously on carbon steel and then see what happens. It will rust.
SS does not rust as you think of regular steel rusting, with a red oxide on the surface that flakes off. If you see red rust it is probably due to some iron particles that have contaminated the surface of the ss and it is these particles that are rusting.
This applies to the 300 grade of ss the 302 303 304 304L 316 316L And so on, now this ss can get a stain on it but it is not easy to do . these grades are used for knifes, medical things, jewelry and much more. these also give you the best shine.
The 18/0 is the 400 grade 416 440a 440b 440c And so forth they will rust some because they do not have the nickel in them they are also much stronger than the 300 grade. the 400 grade is also magnetic, so the myth that ss isn't magnetic is just that a myth.
17-4 ph is one of the strongest ss used on aircraft, lots of military things.
there are over 150 grades of ss but we only use about 30 of them.