CARBURIZATION DETECTION METHOD

PROBLEM TO BE SOLVED: To provide a carburization detection method capable of detecting even fine carburization which is hardly detected by a conventional carburization detection method.SOLUTION: The carburization detection method includes: inserting a carburized material P0 whose carburization on a tube inner surface is already known into an excitation coil 11 and a detection coil 12; determining a value of a parameter K represented by an expression (1) of K=(I N/L) F, where I(A) is a current value of an excitation current supplied to the excitation coil, L is a length (mm) of the excitation coil, N is the number of turns of the excitation coil, and F is a frequency (kHz) of the excitation current supplied to the excitation coil, so that carburization occurring to the carburized material can be detected based upon an output signal from the detection coil; then setting a condition of the excitation coil so as to obtain the value of the parameter K; and then detecting whether carburization is caused on the tube inner surface of the object to be inspected.