PURPOSE: To enhance accuracy, by changing the frequency of a flaw detection ultrasonic wave with respect to the length of a strand.
CONSTITUTION: A wave form of frequency making attenuation quantity min. in accordance with the change of an estimated disconnection position is generated from the end surface of each of the strands 2 constituting a parallel wire strand by a function generator 5 while the estimated disconnection position is changed at every definite length. Said wave form is amplified by an amplifier 6 and the ultrasonic wave corresponding to the output wave form is excited by an ultrasonic probe 4 to be incident on the strand 2 from the cross-section thereof. Thereafter, the reflected wave from the strand 2 is transmitted to a receiver 7 through the probe 4 and the accurate position of a disconnection part is detected from the presence and arrival time of a reflected echo. As mentioned above, since frequency is changed so as to become min. based on estimation such that the disconnection part is present in a predetermined section, the enhancement of flaw detection accuracy is achieved.
KAWASHIMA SADAO
SUGII KENICHI
| JPS61111460A | 1986-05-29 |
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