There are many types of stainless steel, room temperature according to the organizational structure can be divided into several categories1. The austenite size, such as 304, 321, 304, 321, etc.;2. Martensite or iron grain size, such as 430, 420, 410, etc;Austenite size is non-magnetic or weak magnetic, martensite and ferrite are magnetic.Often used as decorative tube plate mostly austenite size of 304 stainless steel material, generally is non-magnetic or weak magnetic, but caused by smelting chemical state may also appear different magnetic fluctuations or processing.  Be especially emphasized here due to the above causes of 304 stainless steel magnetic, and other stainless steel materials, such as 430, carbon steel magnetic completely is not the same level, that is to say 304 magnetic always shows the weak magnetic steel.If stainless steel is weak magnetic or completely without magnetic, should distinguish material for 304 or 304;If the magnetic with carbon steel, show strong magnetic, 304 for judging is not material.304 and 316 are all austenitic stainless steel, for single phase.With weak magnetism.