Patent ID: 7567873

Claim:
A nondestructive inspection method for a surface processed by shot peening in which a steel material processed by shot peening is used as an inspection target to inspect residual stress, comprising the steps of: arranging a coil provided in an inspection circuit on a surface processed by shot peening of a sample of which a state of generation of residual stress is found, the sample being made of the same material as the inspection target, inputting an alternating current signal to the inspection circuit with changing frequency, measuring frequency response characteristics of impedance of the inspection circuit, and acquiring the frequency response characteristics as sample data; arranging the coil provided in the inspection circuit on a surface of the inspection target, inputting an alternating current signal to the inspection circuit with changing frequency, measuring frequency response characteristics of impedance of the inspection circuit, and acquiring the frequency response characteristics as inspection target data; and comparing the inspection target data to the sample data and, based on the state of generation of residual stress found in the sample, inspecting a state of generation of residual stress in the inspection target.