A New Micro Magnetic Bridge Probe in Magnetic Flux Leakage for Detecting Micro-cracks

Journal of Nondestructive Evaluation - Tập 37 - Trang 1-9 - 2018
Erlong Li1, Yihua Kang1, Jian Tang1, Jianbo Wu2
1School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, China
2School of Manufacturing Science and Engineering, Sichuan University, Chengdu, China

Tóm tắt

Magnetic flux leakage (MFL) testing has been widely used as an efficient non-destructive testing method to detect damage in ferromagnetic materials. It’s of great importance to improve the testing capability of MFL sensors. In this paper, a micro magnetic bridge method in MFL of high sensitivity is proposed to detect micro-cracks. This method consists of a micro magnetic bridge core and an induction coil. Furthermore, a novel micro magnetic bridge probe (MMBP) of higher spatial resolution is designed and developed with $$10~\upmu \hbox {m}$$ width between the two sides of this MMBP in the testing magnetic bridge. The lift-off effect of this new MMBP is studied via finite element method and experimental verification. The results show this MMBP can achieve high sensitivity only when working with a micro-lift-off value. To examine the detecting capability of this MMBP, micro-cracks in magnetic particle inspection sensitivity testing pieces are all inspected, and the lowest depth value is only $$7~\upmu \hbox {m}$$ . The MMBP in this paper improves the testing capability of MFL to the micrometre scale and can be widely used to detect grinding micro-cracks in bearing rings.

Tài liệu tham khảo

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