From the classification point of view, the stainless steel is divided into austenitic stainless steel and martensitic stainless steel. 304 is a kind of austenitic stainless steel. Not all stainless steel is not magnetic, only pure austenitic stainless steel is not magnetic. The effective way to eliminate magnetism is solid solution heat.
In the composition of austenitic stainless steel, the valuable alloy has many components, and the general price is higher than martensitic stainless steel. It can be determined by analytical chemistry and metallographic examination.
When the cold deformation of stainless steel is easy to cause Martensite Precipitation, it is especially obvious for 18-8 steel. Martensitic stainless steel is magnetic and is often used to make medical appliance, cutlery, tableware and so on.