| 摘要 |
PROBLEM TO BE SOLVED: To an electromagnetic ultrasonic flaw detecting device capable of not simply the detection of defects but also the evaluation of the size of a defect through the use of a small-size transducer. SOLUTION: This flaw detecting device is constituted of an annular PPM electromagnetic ultrasonic transducer 1 to excite and transmit ultrasonic waves into an object whose flaw is to be detected and to receive returned ultrasonic waves, a sound pressure determined means 102 to determine the sound pressure of the received ultrasonic waves, an oscillator 8 to transmit an excitation signal to the annular PPM electromagnetic ultrasonic transducer 1 while sweeping frequencies, a resonance frequency determining means 103 to detect as a resonance frequency the frequency at which the sound pressure becomes maximum from the distribution of the sound pressure obtained as a function of the frequencies via determining operation of excitation, reception, and sound pressure associated with frequency sweep, and a defect condition determining means 104 to determine the presence or absence of a defect or the size of a defect according to the resonance frequency determined by the resonance frequency determining means 103. |
