It is a common question, raised when we talk about stainless steel. The answer is much more complicated than a simple yes or no.

In the food industry the most popular used types of stainless steel are grades 304 and 316. Those two grades belong to the austenitic stainless steel family. The austenitic stainless steel structures are totally non-magnetic. So theoretically, grades 304 and 316 should be non-magnetic.
However any process that can change the micro-structure of stainless steel can cause austenite to be converted into ferromagnetic martensite or ferrite forms of iron. These processes are cold-working (polishing, blasting, grinding, rolling) and welding.

Generally speaking the 304 stainless steel grades can attain a quite strong magnetic response to the cold-working process compared to the grade 316 (hot-working process) which remain non-magnetic in most cases.

Link to all Stainless Steel product range: Stainless Steel Equipment