Flaw detection for microcrack in spring steel and estimation of crack shape with eddy current testing

Article type: Research Article

Authors: Fukuoka, Katsuhiro^a; | Hasegawa, Ryo^a

Affiliations: [a] University of Shiga Prefecture, Hikone, Shiga, Japan

Correspondence: [*] Corresponding author: Katsuhiro Fukuoka, 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: [email protected]

Abstract: Non-uniform permeability distributions in steel materials reduce signal-to-noise (S/N) ratios in eddy current testing (ECT). Therefore, steel materials must be magnetised to reduce magnetic noise. In this study, microcrack detection in spring steel materials using ECT was considered. An ECT system that was able to detect 40-μm-deep crack with S/N ratio of 3 or more was developed. In addition, the depth profile of microcracks using the detection signal was accurately estimated.

Keywords: Eddy current testing (ECT), microcrack, spring steel, signal-to-noise (S∕N) ratio, crack shape estimation

DOI: 10.3233/JAE-171123

Journal: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 4, pp. 1267-1274, 2019