Why don't magnets stick to stainless steel?
It is a common misconception that all metals are magnetic. With stainless steel, the magnetic property depends on the crystal structure of the material. Most everyday stainless steel products are not magnetic.
Austenitic vs. Ferritic Steel
The most commonly used types of stainless steel (such as type 304 and 316) are 'austenitic'. The addition of nickel changes the atomic structure in such a way that the material no longer reacts to magnets.