Patent ID: 8074520
Filing Date: 2011-12-13
Classification: G01N

Abstract:
1. An ultrasonic inspection method utilizing a resonance phenomenon of continuously transmitting a wideband ultrasonic wave by a transmission probe and receiving a wideband ultrasonic wave from an inspection target by a reception probe, wherein a measurement is performed with the transmission probe and the reception probe being located on a surface of a cylindrical pipe on a cross-section perpendicular to a direction along a cylindrical axis of the pipe, where the length of a curve connecting the centers of the pair of probes is labeled as “a” and the curve is matched to an arc of the cross-section; the method comprising: executing a first step of transmitting a wideband ultrasonic wave from the transmission probe toward the central point of the cross-section of the cylindrical pipe perpendicular to the direction along to the cylindrical axis of the pipe by an externally specified number of times (n executing the first step each time when the pair of probes are translated in the direction along the cylindrical axis of the pipe by a predefined or externally given predetermined value ΔL while the pair of probes are kept as distanced by the interval “a”; and executing a second step of performing the first step by an externally given predetermined number of times n executing a third step of calculating a longitudinal primary resonant frequency f  where the thickness of the inspection target is W (mm), the longitudinal wave sonic speed is V successively performing analyses of step 4, step 5 and step 6 shown below using sizing coefficients n step 4: step by which GAO is processed by Fourier transformation to find F has a decreasing function of f=f  using the sizing coefficient n step 5: step by which a maximum amplitude of each component wave GA  is created, and the component wave GA step 6: step by which an n