People often attracted by the magnet stainless steel, and verify the authenticity of their advantages and disadvantages, do not smoke, non-magnetic, that is the genuine; suck those magnetic, is considered to be counterfeit fakes. In fact, this is an extremely one-sided, no practical method to identify errors. Many kinds of stainless steel at room temperature according to the organizational structure can be divided into several categories: 1, austenitic: If 304,321,316,310; 2, martensite or ferrite: as 430,420,410, etc. ; austenitic type is non-magnetic or weakly magnetic, martensite or ferrite is magnetic. Usually used as a decorative tube plate is austenitic stainless majority of 304, in general, is a non-magnetic or weakly magnetic, but the chemical composition fluctuations caused by smelting or processing may occur in different magnetic state, but can not be considered counterfeit or substandard, which is what causes it? Austenitic mentioned above are non-magnetic or weakly magnetic, and martensite or ferrite is magnetic, due to improper segregation smelting or heat, can cause a small amount of martensite in austenitic 304 stainless steel or ferrite body tissue. Thus, the 304 will carry the weak magnetism. Further, 304 stainless steel after cold working to the martensite transformation structure also, the greater the degree of cold deformation, more martensite transformation, the greater the magnetic steel. Like steel batch numbers, production Φ76 tube, no significant magnetic induction, production Φ9.5 tubes, cold bending deformation due to a larger number of magnetic induction is obvious, because the production of square and rectangular tube pipe deformation than large, especially knuckle part of the more intense magnetic distortion is more evident.