| 摘要 |
PURPOSE:To effectively correct the sensitivity to inspect a flaw of a surface layer by monitoring the level of the sneak echoes. CONSTITUTION:An ultrasonic flaw detector 14 is set for a metallic square material 10 as a to-be-inspected member, for example, 145mm square SU304 billet. Preferably 0.5-0.7MHz ultrasonic waves are projected from an emission surface 30 of an ultrasonic probe 34. The surface wave circulates one round of the square material 10 to be detected as a sneak echo by the probe 34. When the material 10 has no flaw, and if the probe 34 traces well, that is, the propagating amount of ultrasonic waves in the material 10 is good, clear echoes are obtained. If the propagating amount is not good, clear echoes cannot be obtained. Therefore, whether or not, the probe 34 traces well is evaluated by monitoring the level of the sneak echoes. In other words, when the sneak echoes are monitored, it can be evaluated whether or not the ultrasonic flaw detection is conducted reliably, and hence the effective correction of sensitivity becomes possible. |
