ULTRASONIC THICKNESS MEASURING DEVICE AND ULTRASONIC THICKNESS MEASURING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a device and method capable of automatically measuring reduction in thickness of a material of a pipe or the like at low cost and, even if the reduction in thickness locally occurs, detecting the reduction in thickness.SOLUTION: A measuring device 1 measures thickness of a material 50 using EMAR based on a resonant frequency of an electromagnetic ultrasonic signal which is propagated within the material 50. The measuring device 1 comprises an EMAT 11 for transmission and an EMAT 12 for reception. The EMAT 11 for transmission simultaneously transmits electromagnetic ultrasonic signals of different frequencies to the material 50 while temporally varying or superimposing them in a transmitting position 21 on a surface of the material 50. The EMAT 12 for reception receives electromagnetic ultrasonic signals which are propagated within the material 50, in a receiving position 22 separated from the transmitting position 21 on the surface of the material 50. Thus, based on a resonant frequency indicating a peak of the received electromagnetic ultrasonic signals, thickness DB in a location 52 where thickness is reduced, between the transmitting position 21 and the receiving position 22 can be measured using EMAR.