Why is the processed stainless steel magnetic?

Austenite is non-magnetic or weak magnetic, while martensite or ferrite is magnetic. During the processing of jinyiding stainless steel, it is found that a small amount of martensite or ferrite structure in Austenitic 304 stainless steel will be produced due to the component segregation or improper heat treatment during smelting. In this way, 304 stainless steel will have weak magnetism.
In addition, the microstructure of 304 stainless steel will be transformed to martensite after cold working. The larger the cold working deformation, the more martensite transformation, the greater the magnetic properties of the steel. The stable austenite structure can be restored by high temperature solution treatment, thus eliminating magnetism.