A Nondestructive Testing Method of Incremental Permeability Based on Permanent Magnet Movement Magnetization

Typical Incremental permeability (IP) requires a high power supply to generate a bias magnetic field that periodically magnetizes the testing samples, making it difficult to apply to occasions where high power supply is short. To solve this problem, this paper presents a low power NDT method based on IP, which is characterized in that the permanent magnets are used to form a bias magnetic field, and the sample is magnetized aperiodically by moving the permanent magnet in one direction. Finite element simulation is used to compare the magnetic fields formed by permanent magnets with different number of blocks and distance between them, as well as the hysteresis curves under magnetic excitation, and a finite element simulation method (FEM) of IP is given. Our experiments used the new method to estimate the yield strength of steels, demonstrating that the proposed method can obtain an approximately accurate result, and its power consumption is less than 2 W.