People often magnet adsorption of stainless steel, to verify its advantages and disadvantages and authenticity, do not smoke non-magnetic, that is genuine; suction magnetic, that is counterfeit fake. In fact, this is a very one-sided, unrealistic way to identify the wrong.

A wide range of stainless steel, according to the organizational structure at room temperature can be divided into several categories:

1, austenitic type: such as 304,321,316,310;

2, martensite or ferrite type: such as 430,420,410;

Austenitic type is non-magnetic or weak magnetic, martensite or ferrite is magnetic.

Most of the stainless steel, which is usually used as a decorative tube sheet, is mostly austenitic 304 material. Generally speaking, it is magnetic or weak, but magnetic properties may occur due to chemical composition fluctuation or processing status, but this can not be considered Fake or unqualified, what is the reason for this?

The above mentioned austenite is non-magnetic or weak magnetic, and martensite or ferrite is magnetic, due to smelting component segregation or improper heat treatment, will cause austenitic 304 stainless steel in a small amount of martensite or iron Body tissue. In this way, 304 stainless steel will be with a weak magnetic.

In addition, 304 stainless steel after cold processing, the structure will be transformed into martensite, cold forming the greater the degree of deformation, the greater the transformation of martensite, steel, the greater the magnetic. As a number of steel strip, the production Φ76 tube, no obvious magnetic sense, the production Φ9.5 tube, due to cold bending deformation, magnetic induction is obvious, the production of rectangular tube deformation due to large diameter, especially the angle Part, deformation more intense magnetic more obvious.