Patent ID: 9638668
Date: 2017-05-02
CPC Classifications: C21D,G01N

Claim:
1. A surface property inspection apparatus for inspecting surface properties of an object under inspection subjected to surface processing, comprising: an AC bridge circuit; an AC power supply for supplying AC power to the AC bridge circuit; and an evaluation apparatus for evaluating the surface properties of the object under inspection based on an output signal from the AC bridge circuit; wherein the AC bridge circuit has a variable resistor configured so that the distribution ratio is variable between a first resistor and a second resistor, an inspection detector furnished with a coil for creating an AC magnetic field and exciting an eddy current in the object under inspection, and a reference detector for inspecting a reference state serving as reference for comparing with the output from the inspection detector; and whereby the first resistor, the second resistor, the reference detector, and the inspection detector constitute the AC bridge circuit; and wherein the evaluation apparatus evaluates the surface properties of the object under inspection based on an output signal from the AC bridge circuit, in a state whereby AC power is supplied to the AC bridge circuit, the inspection detector detects an electromagnetic properties of the object under inspection and the reference detector detects a reference state, and wherein the coil is wound to surround a surface property inspection region of the object under inspection, and an eddy current is excited in the surface property inspection region by supplying AC power to the coil.