All I know is that fridge magnets stick to the SS on my fridge, but not my neighbor's. From that small sample of empirical evidence, I deduce there are different alloys of SS.

(In another sample of kitchen science, the same neighbor demonstrated that his cell phone will not work inside his (unpowered!) microwave. It does in mine, so his is superior in shielding radiation. My deduction is that he spends more on appliances than I do.)