Development of ECT probe for flaw detection of microcrack in spring steel material

Issue title: Proceedings from the 17th International Symposium on Applied Electromagnetics and Mechanics (ISEM 2015)

Guest editors: Fumio Kojima, Futoshi Kobayashi and Hiroyuki Nakamoto

Article type: Research Article

Authors: Fukuoka, Katsuhiro

Affiliations: The University of Shiga Prefecture, 2500 Hassaka-cho, Hikone, Shiga 522-8533, Japan. Tel.: +81 749 28 9554; Fax: +81 749 28 9554; E-mail: fukuoka.k@usp.ac.jp

Abstract: Nonuniform permeability distribution in ferromagnetic materials creates noise in eddy current testing (ECT). To overcome this problem, ferromagnetic materials are magnetized and inspected in the magnetic saturation state to reduce noise. In this study, I targeted a spring steel material that is not easily magnetized and developed an ECT system with an encircling coil probe that was able to detect microcracks. Clear signals for 70 μm deep microcracks were obtained with a signal-to-noise ratio of 3.5 by magnetizing a test object using the optimal exciting current.

Keywords: Eddy current testing (ECT), encircling coil probe, spring steel, magnetic noise, magnetization

DOI: 10.3233/JAE-162108

Journal: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 3-4, pp. 1177-1183, 2016