1, because 304 stainless steel after cold working, the organizational structure will also be transformed to martensite, the greater the degree of cold working deformation, the more martensite transformation, the greater the magnetic. Stainless steel after cold upsetting and cold rolling their molecular arrangement will be changed resulting in a slight magnetic, but this is only physical, chemical is not changed.
2, in addition, such as a batch of stainless steel wire, made straight branch, no obvious magnetic, but bend it into a rectangle or round, due to the deformation of the cold bending of the larger and produce some magnetic, especially the corner of the magnetic part of the more obvious.
3, to complete the elimination of the above 304 stainless steel magnetism, can be restored through high temperature treatment of stable austenitic organization, thus eliminating the magnetism.
4, often people think that the test of stainless steel good or bad with a magnet, the magnet does not suck, no magnetism, the real thing; suck if there is magnetic, it is considered to be counterfeit -. In fact, this is an extremely one-sided, not practical and wrong identification method.
5, 304 stainless steel is a common material in stainless steel, density 7.93 g/cm3, the industry is also called 18/8 stainless steel. High temperature resistance of 800 degrees, with good processing performance, high toughness, widely used in industry and furniture decoration industry and food medical industry.
6, 304 is a general-purpose stainless steel, it is widely used in the production of equipment and machine parts requiring good overall performance (corrosion resistance and molding). In order to maintain the corrosion resistance inherent in stainless steel, the steel must contain more than 18% chromium, more than 8% nickel content. 304 stainless steel is produced in accordance with the U.S. ASTM standard stainless steel grade.
7, in general, stainless steel with magnetic, there are also non-magnetic. Austenitic type is non-magnetic or weakly magnetic, such as 201, 202, 304, 316, etc.; martensitic or ferritic is magnetic, such as 430, 420, 410, etc..
Special reminder is that the magnetic properties of 304 stainless steel caused by the above reasons are not the same level as the magnetic properties of other materials of stainless steel, such as 430, carbon steel, etc. That is to say, the magnetic properties of 304 stainless steel are always weakly magnetic.
Simply put, if the stainless steel is weakly magnetic or completely non-magnetic, it should be identified as 304 or 316 material; if the same as carbon steel magnetism, showing strong magnetism, it is identified as not 304 material.