Sensitivity calibration method and apparatus of the eddy current flaw detector

摘要

PROBLEM TO BE SOLVED: To provide a method and device capable of comparably easily and precisely performing sensitivity calibration of an eddy current tester in a short time.;SOLUTION: A plurality (N pieces) of the eddy current sensors for detecting the flaw in a running metal band are arranged by winding primary coils on the center legs of E cores, and on both the legs, the secondary coils are differentially connected, and disposed in width direction of a metal band, wherein a tape conductor longer than the whole length of the plurality of eddy current sensors arranged in width direction is disposed under the spaces between the central legs and either of outer legs. At this point, the output V_1k (k=1 to N, V_1k0) are read, and the tape conductor is displaced under the space between the central legs and another outer legs, the output of each eddy current sensor - V_2k (k=1 to N, V_2k0) are read, thereby the sensitivity calibration is performed by making the difference of both the outputs V_1k-(-V_2k) a specific value.;COPYRIGHT: (C)2006,JPO&NCIPI