The reason why stainless steel end caps become magnetic after stamping.

Stainless steel end caps sometimes become magnetic after stamping, which can be quite troublesome. So why do stainless steel end caps become magnetic after stamping? There are three main reasons.

First, the raw materials are not of sufficient quality and may contain iron and other substances.

Secondly, there are areas in the production process where the stainless steel comes into contact with carbon steel. This is mainly caused by work hardening; the deformation during stamping causes the stainless steel to develop deformation martensite, resulting in magnetism.

On the other hand, during heat treatment, steel undergoes inconsistent volume expansion due to microstructural changes, resulting in structural stress. The ultimate result of the structural stress changes in stainless steel heads is that the surface is under tensile stress and the core is under compressive stress, which is exactly opposite to the thermal stress.