Affiliations: [a] School of Manufacturing Science and Engineering, Sichuan University, Chengdu, China | [b] Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal | [c] School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, China
Correspondence:
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Corresponding author: Jianbo Wu, School of Manufacturing Science and Engineering, Sichuan University, Chengdu, 610065, China. E-mail: wujianbo@scu.edu.cn
Abstract: In high-speed scanning MFL inspection for a steel pipe, according to Lenz’s Law, motion-induced eddy current (MIEC) is induced by relative movement between axial magnetizer and the inspected pipe. On the one hand, magnetic field generated by MIEC will change the magnetization intensity of the pipe and thereafter change the signal amplitude; on the other hand, it will also cause signal baseline shift by altering background magnetic field. In this paper, the effect of MIEC on axial MFL inspection is investigated by theoretical analysis, finite element simulations, and high-speed experiments. It is found that at different locations MIEC causes different change trends for both the background magnetic field and magnetization intensity, leading to sensitivity difference, which should be taken into consideration in the high-speed MFL inspection for a steel pipe.
Keywords: Steel pipe, high-speed magnetic flux leakage (MFL) inspection, motion-induced eddy current (MIEC) and signal characteristics
