Magnetic Flux Leakage Course of Inner Defects and Its Detectable Depth

Chinese Journal of Mechanical Engineering

Erlong Li¹  Jianbo Wu¹  Wenqiang Wu¹  Yihua Kang² 

[1] School of Mechanical Engineering, Sichuan University, 610065, Chengdu, China;School of Mechanical Science and Engineering, Huazhong University of Science and Technology, 430074, Wuhan, China;

关键词: Magnetic flux leakage (MFL) testing;    Inner defect;    Buried depth;    Permeability;   

DOI  :  10.1186/s10033-021-00579-y

来源: Springer

【 摘 要 】

As a promising non-destructive testing (NDT) method, magnetic flux leakage (MFL) testing has been widely used for steel structure inspection. However, MFL testing still faces a great challenge to detect inner defects. Existing MFL course researches mainly focus on surface-breaking defects while that of inner defects is overlooked. In the paper, MFL course of inner defects is investigated by building magnetic circuit models, performing numerical simulations, and conducting MFL experiments. It is found that the near-surface wall has an enhancing effect on the MFL course due to higher permeability of steel than that of air. Further, a high-sensitivity MFL testing method consisting of Helmholtz coil magnetization and induction coil with a high permeability core is proposed to increase the detectable depth of inner defects. Experimental results show that inner defects with buried depth up to 80.0 mm can be detected, suggesting that the proposed MFL method has the potential to detect deeply-buried defects and has a promising future in the field of NDT.

【 授权许可】

CC BY