Why is 304 316L stainless steel magnetic? How to demagnetize

Why is 304 316L stainless steel magnetic? How to demagnetize?

Martensitic|304 Stainless Steel|Magnetic|316l Stainless Steel|Ferrite

Usually austenitic 304 material, generally speaking, is non-magnetic or weakly magnetic, but due to smelting caused by fluctuations in chemical composition or processing state may also appear magnetic, but this can not be regarded as impostor or unqualified, what is the reason for this?

Austenite is non-magnetic or weakly magnetic, and martensite or ferrite is magnetic, due to the smelting of compositional segregation or improper heat treatment, will cause austenitic 304 stainless steel in a small amount of martensite or ferrite organization. In this way, 304 stainless steel will have a weak magnetism.

In addition, 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 properties of steel. As a batch number of steel strip, the production of Φ76 pipe, no obvious magnetic sensation, the production of Φ9.5 pipe. Because of the deformation of bending larger magnetic sense will be obvious, the production of square rectangular pipe because the deformation is larger than the round pipe, especially the corner part, the deformation is more intense magnetic more obvious.

To completely eliminate the magnetic properties of 304 steel caused by the above reasons, through high-temperature solution treatment to restore stable austenitic organization, thereby eliminating the magnetic properties.

In particular, the magnetic properties of 304 stainless steel caused by the above reasons, and other materials of stainless steel, such as 430, carbon steel magnetism is not the same level, that is to say, the magnetic properties of 304 steel is always shown as a weak magnetism.