Remanent magnetization of steel plates after being magnetized by moving magnets

• Published in: Journal of magnetism and magnetic materials 2023-07, Vol.578, p.170818, Article 170818
• Main Authors: Shan, Liu, Jinyu, Ma, Zhoumo, Zeng, Jian, Li, Hao, Feng, Xiaobo, Rui, Hui, Zhang, Xinjing, Huang
• Format: Article
• Language: English
• Subjects: Magnet; Remanent magnetization; Steel plate
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2023.170818

•Remanent magnetization of steel plates magnetized by moving magnets are studied.•Single and dual magnets have equivalent magnetization effect on a steel plate.•Initial irregular magnetization of steel plates can be homogenized by strong external magnetization.•When steel plate is long enough, remanent magnetic flux density near the surface is zero. Inconsistent initial magnetization of ferromagnetic specimens may result in low signal-to-noise ratio and poor consistency in detecting defects and stress anomalies of magnetic methods. One of the solutions to the problem is to magnetize specimen in advance and make it magnetized uniformly. Via theoretical analysis, finite element simulation and experiment verification, the distribution of remanent magnetization and remanent flux density of steel plates after being magnetized by moving single and dual magnets is studied. The results show that the remanent magnetization of the steel plate becomes uniform and in the same tangential direction of the magnet moving. The remanent magnetization inside the steel plate is layered, and the magnetization between different layers may be opposite. However, the magnetization of each layer is uniform, and the tangential remanent magnetization is large, while the normal remanent magnetization is small. The longer the length of the steel plate specimen, the longer the flat area of the magnetic flux density near the surface after magnetization, and the value of the flat area is closer to zero. The research results provide important guidance for the magnetization method and the defect detection scheme design.