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 is non-magnetic or weak magnetic, martensite and ferrite magnetic, due to improper smelting composition segregation or heat treatment, can cause a small amount of martensite in the austenitic stainless steel 304 or ferrite organization.In this way, will with weak magnetic 304 stainless steel.In addition, 304 stainless steel after cold working, the organization structure will be to the martensitic transformation, the greater the degree of cold deformation, martensitic transformation, the magnetic steel.Because ling bending deformation is magnetically sensitive to some apparently, rectangular tube production due to the deformation is bigger than circular tube, especially the Angle, more intense magnetic more obvious deformation.To eliminate the causes of 304 magnetic steel treated by high temperature solid solution stability returns austenitic organization, thus eliminating magnetism.