QUOTE(SLITS @ Feb 25 2009, 05:15 PM)
500 has the most iron and rusts like a teener and is magnetic
400 has less and rusts less and I don't remember if it has magnetic qualities (most catalytics shells are this material I think)
300 is the shiny shit that doesn't rust and is not magnetic.
Don't want to seem picky, but this one hurt me. We had a customer put a magnet on a product and say "That ain't 302!" Problem is that it was. They're considered non-magnetic but a number of the 300 alloys are actually weakly magnetic, and weirdly enough get more so when they're cold-worked. Even more so when they come from China, probably.
I didn't know that, got caught flat-footed, and stood there with my mouth open. And for good order's sake some will oxidize a bit, depending on grade and conditions. 316 is considered "marine grade", for example, while 302 and 304 are not for marine environments.