| 摘要 |
PROBLEM TO BE SOLVED: To speedily detect flaws present at a material surface layer part on line by a transmission method with use of surface waves of ultrasonic waves and, correctly estimate a depth of the surface defect. SOLUTION: There are set an ultrasonic probe 3 for transmission which generates surface waves of ultrasonic waves to a surface layer part of a body 1 to be inspected, and an ultrasonic probe 6 for reception which receives the surface waves passing the surface layer part of the body 1, thereby detecting a defect 2 of the surface layer part of the material. A transmission waveform 11 obtained by gathering burst waves of two or more different frequencies separately in time is transmitted by an optional waveform-generating device 10 to the ultrasonic probe 3 for transmission. In receiving passing surface waves of respective frequencies by the ultrasonic probe 6 for reception, the waves are detected by a gate circuit 15 in accordance with respective arrival times, and furthermore, a transmission intensity of each frequency is obtained by peak hold circuit 16a, 16b, 16c and do forth. A depth of the defect is estimated from the transmission intensity by a depth-estimating part 18. |
