Stainless Steel sheetmetal bolt kits- do they rust?

[Steeveedee]

It is important to note that both 400 and 300 series stainless steel still contain iron. 300 series has enough chromium that the material exposed to oxygen forms a face-centered cubic molecular structure, so that the chromium gets the oxygen and then blocks the oxidation of the deeper structure, in much the same way that aluminum will not continue to corrode once a layer of oxide forms on the surface. Galling of stainless fasteners has to do with the similar metals slightly welding with friction. If you use different alloys of stainless (say, 304 bolts and 316 nuts), you can avoid this issue. Anti-seize is fine to avoid the galling problem if one used the same alloy for all the fasteners. Chromium on vehicles is only a few millionths of an inch thick, so eventually the oxygen in the air will get to the base metal. And yes, a sufficient amount of chromium in your stainless will reduce its magnetic moment. Interesting fact- nickel metal (not coins- they are an alloy of copper and nickel) is attracted to a magnet just like iron.