Magnetic SS has about 18 - 20% chromium - it's basically chrome-iron. My window hinges are 'SS' and go slightly rusty; the new egress hinges aren't paramagnetic. I've just bought some dessert spoons that boast SS and they're magnetic. 'Proper' SS for cutlery, pans etc. will be 18% Cr 8% Ni; Cr to stop rusting (ha!) and Ni as anti-tarnish. Ideally, ferritic SS should be more than 18%. At one place that I worked, some wheel trim was CrFe at 18% and Rolls Royce was, IIRC 22%. Made a lot of difference in saltspray after chrome plating.