Steel plant as well as the magnetic flux leakage inspection device and magnetic flux leakage inspection method

摘要

PROBLEM TO BE SOLVED: To provide a leakage flux inspecting method for a ferromagnetic metal specimen capable of detecting even a micro defect, with high detection precision. ;SOLUTION: A magnetic inspection equipment 4 is provided along a conveying passage for a steel plate 1. The equipment 4 is composed mainly of magnetizers 5a, 5b, magnetic sensors 6a, 6b, and a signal processor 7. The sensor 6a measures a leak magnetic flux from the steel plate 1 in a condition magnetized by the magnetizer 5a. The sensor 6b measures a leak magnetic flux from the steel plate 1 in a condition magnetized by the magnetizer 5b. The signal processor 7 operates fellow magnetic signals in the same position of the steel plate 1 detected by the sensors 6a, 6b, so as to reduce noise magnetic fluxes. A defect signal is thereby intensified reletively to enhance an S/N ratio.;COPYRIGHT: (C)2000,JPO