US Patent 10048227 Surface property inspection method and apparatus

The present invention provides a surface property inspection method and apparatus for inspecting the surface properties of a test object subjected to two stages of shot peening. The present invention is an apparatus 1 includes an AC power supply, an AC bridge circuit, and an evaluation apparatus. The AC bridge circuit is constituted by a variable resistor, a reference detector and inspection detector. The inspection detector includes a coil wound so as to oppose the surface property inspection area of the test object M; an eddy current is excited in the test object M by supplying AC power to the coil. A pass/fail judgment of the first shot peening can be made by inspecting the surface properties of a test object subjected to a second shot peening only after the second shot peening is completed.