SURFACE PROPERTY INSPECTION METHOD AND APPARATUS

摘要

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.

主权项

1. A surface property inspection method for inspecting a surface property of a shot peened test object, comprising steps of:
an inspection apparatus preparation step for preparing a surface property inspection apparatus, wherein the surface property inspection apparatus comprises:
an AC bridge circuit;an AC power supply for supplying AC power to the AC bridge circuit; andan evaluation device for evaluating the surface property of the test object based on an output signal from the AC bridge circuit;wherein the AC bridge circuit comprises:
a variable resistor in which the distribution ratio can be varied between a first resistor and a second resistor,an inspection detector comprising a coil capable of exciting AC magnetism, formed so that said coil can be disposed to excite an eddy current in the test object, anda reference detector, in which a reference test object having the same structure as the test object is disposed, and detecting a reference state which serves as a reference for comparison with an output from the inspection detector; andwherein the first resistor, the second resistor, the reference detector, and the inspection detector constitute the bridge circuit; a threshold value setting step for determining a threshold value used in evaluating the surface property of the test object in the evaluation device; an eddy current excitation step for exciting the eddy current by the inspection detector in the test object subjected to a first shot peening for imparting residual stress from a surface into deep portions and a second shot peening for performing, after the first shot peening, a lower strength shot peening than the first shot peening, thereby imparting further residual stress close to the surface; and a pass/fail judgment step for using the evaluation device to compare the threshold value with the output signal output from the AC bridge circuit during the eddy current excitation step implemented after the second shot peening, and then judging whether the first shot peening was correctly performed.