| 摘要 |
PURPOSE: To improve the flaw position detection accuracy at the time of flaw detection by V-transmission-scanning a moving ultrasonic probe, obtaining the intra-material sonic velocity distribution for the refractive angle, and estimating the sonic velocity of a fixed ultrasonic probe having the refractive angle different from that of the moving ultrasonic probe based on the obtained sonic velocity distribution. CONSTITUTION: When one moving ultrasonic probe 1 having the refractive angle 60 deg., for example, is fixed near the weld section 8 of a measured member and the other probe 1 is scanned perpendicularly to the weld section 8, not only the echo when the angle θ obtained from the distance (y) between the probes 1 and the thickness (t) of a base material is equal to the refractive angle 60 deg. but also the echo over the beam spread range of about 64-72 can be received, and the correlation between the intra-material sonic velocity (e.g. 3120-3230m/s) obtained from the beam path and transmission/reception time and the actual refractive angle is obtained. When the refractive angle of the fixed ultrasonic probe is set to 65 deg., the sonic velocity at the actual refractive angle of about 71 deg. can be accurately estimated to 3220m/s, and the position of the flaw detected by coarse flaw detection can be correctly set. |
