Study on metal magnetic memory signal of buried defect in fracture process

To study the magnetic memory signal characteristics of buried defects and for timely detection of the buried defects and stress concentration areas of metal components, defect samples with different burial depths were fabricated. The relationship between the magnetic memory signals and burial depths of the defects was studied. The variation in the magnetic memory signals of the buried defects was studied under different load stages (initial loading, mid-loading, critical fracture, and after fracture). The results show that the magnetic memory detection method can detect buried defects, and the strength of the magnetic field and its gradient decrease with an increase in the burial depth. The strength of the same defect magnetic field and its gradient decrease initially and then increase under the action of an external load, and then, increase sharply at the critical fracture stage. The research results are of considerable significance for the detection of defects in ferromagnetic materials.