| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface defect detecting device adapted to detect a surface defect by using a surface wave and specify the position of the surface defect accurately. SOLUTION: This surface defect detecting device is so constructed that oscillation sensors 1a, 1b for oscillating a surface ultrasonic wave in the opposite directions at 180 deg. and receiving sensors 2a, 2b disposed near by on the same section as the sensors 1a, 1b for detecting the surface wave are provided in a pair, two pairs in total at positions spaced from each other by 90 deg.. The detecting device includes an oscillator 4 having a timing circuit 5 for alternately switching the oscillation of the oscillation sensors 1a, 1b, a gate unit 8 for detecting a defect signal among signals received by the receiving sensors 2a, 2b and amplified, a determining device (comparator 11) for discriminating a harmful defect according to the magnitude of a defect signal detected by the gate unit 8, and a discriminator 12 for discriminating the position of a defect according to an output signal from the comparator 11 and a previously input logic. |
