FLAW DETECTION METHOD BASED ON ELECTROMAGNETIC ULTRASONIC WAVE AND ELECTROMAGNETIC ULTRASONIC FLAW DETECTOR

摘要

PROBLEM TO BE SOLVED: To provide a flaw detection technique based on an electromagnetic ultrasonic wave so as to be able to improve the flaw detection ability.;SOLUTION: An electromagnetic ultrasonic flaw detector is provided with a static magnetic field generating magnet 5 generating a static magnetic field inside a tested material 1, transmitting means 3 and 13 feeding pulse current to a transmission coil 3 so as to generate an eddy current inside the tested material 1, and receiving means 7 and 13 receiving a reflection echo of the ultrasonic wave, which is generated by oscillation of the surface of the tested material 1 caused by the static magnetic field and the eddy current generated inside the tested material 1, from a flaw detection part in the tested material 1. The receiving means 7 and 13 switch a receiving coil 7 receiving the reflection echo according to a transmission frequency so as to change a receiving position. In this way, the receiving position is changed in compliance with the ultrasonic wave transmission frequency defining an ultrasonic wave incident angle, so that the reflection echo can be received in a reflection echo arrival position. Consequently, flaw detection ability can be improved because reflection echo with a sufficient size can be received.;COPYRIGHT: (C)2002,JPO