EDDY CURRENT FLAW DETECTION METHOD AND EDDY CURRENT FLAW DETECTOR

PROBLEM TO BE SOLVED: To perform the flaw detection of a non-magnetic material containing a partial ferromagnetic phase in its surface part like high manganese cast steel. SOLUTION: In the flaw detection of a member containing a partial ferromagnetic phase in its surface part, the member is subjected to overlapping excitation by two high and low frequencies and the primary output by the presence of the partial ferromagnetic phase or a crack is separated into outputs of two original high and low frequencies. A part large in both outputs is discriminated as a part due to the presence of the partial ferromagnetic phase and a part large in the output of high frequency and small in the output of low frequency is discriminated as a part due to the presence of a crack.