摘要 |
PROBLEM TO BE SOLVED: To calculate the position of a reflecting source from the propagating distance of a detected reflected echo in a flaw determination method for body to be inspected by tandem method and perform a highly reliable determination from the information conforming to the reality of the reflection source. SOLUTION: The position of the reflecting source of the detected reflected echo is calculated from the propagating distance (r) calculated from the time from the transmission of ultrasonic wave from a transmitting angle beam probe 12A to the receipt of the reflected echo by a receiving angle beam probe 12B and the sound velocity of the ultrasonic wave; the distance (h) from the surface of a rail 1 abutting on the transmitting and receiving angle beam probes 12A and 12B to the bottom (back surface) thereof; and the position x0πd between the angle beam probes 12A and 12B. |