Study on Metal Magnetic Memory Testing Mechanism

Compared with traditional nondestructive testing technologies, the method of metal magnetic memory (MMM) is a more effective way in the earlier injury diagnosis of ferromagnetic materials, but the investigation of the MMM testing mechanism is limited. In order to study the mechanism of MMM method, in this article, the relationship between stress concentration state and spontaneous magnetic flux leakage (SMFL) signal is analyzed by quantum theory. The results demonstrate that the fundamental reason for SMFL is lattice distortion leaded by stress concentration, and the rising of stress causes the SMFL signal changing linearly. The theoretical calculation results in this article are in very good agreement with experimental results.