| 摘要 |
PURPOSE: To realize a method for detecting a stripping defect at a brazed part of a specimen. CONSTITUTION: An ultrasonic beam 4 transmitted from an ultrasonic probe 1 passes through a delay member 2 and enters into a specimen 3. An echo 8 from a defect 5 in the specimen 3 is received by the ultrasonic probe 1 and the number thereof is counted. Since the ultrasonic beam 4 arrives at the defect 5 while being delayed through the delay member 2 and the defect echo 8 can avoid the dead band 6, the defect can be detected accurately. Since a stripping defect 14 has wider receiving area of ultrasonic beam 4 than other defect and the ultrasonic beam 4 is reflected a plurality of times, it can be identified by counting the number of reflection times of defect echo 8. |
