Is magnetism a criterion for distinguishing stainless steel? People often use magnets to attract stainless steel handles to verify their pros and cons. It is considered to be good if it does not attract and no magnetism; otherwise, it is considered to be counterfeit. In fact, this is an unrealistic identification method. It is very likely to suffer a loss by relying on the traditional method of identifying stainless steel handles whether they are magnetic or not.
Because the quality of stainless steel cannot be judged by the naked eye, it can only be used for testing. If chromium is added to stainless steel, it can be magnetically attracted, but it is only a matter of magnetic permeability. The austenite type is non-magnetic or weakly magnetic, martensite or Ferrite type is magnetic.
Generally speaking, there are many kinds of stainless steel, which can be divided into austenite and martensite or ferrite according to the structure at room temperature. The austenitic type is non-magnetic or weakly magnetic, and the martensite or ferritic type is magnetic. However, this is not necessarily the case. For example, the austenitic 304 material usually used for stainless steel handles is generally non-magnetic, but it may also appear magnetic due to fluctuations in chemical composition or different processing conditions caused by smelting, which cannot be considered counterfeit or unqualified. In addition, after cold working of 304 stainless steel, the structure will also be transformed to martensitic. The greater the cold working deformation, the more martensitic transformation and the greater the magnetic properties of the steel. On the contrary, the 200 series stainless steel of lower quality is likely to be non-magnetic, and it is a big mistake to judge that it is genuine stainless steel.