| 摘要 |
PURPOSE:To facilitate quantitative judgement on the results of flaw detection with a higher measuring accuracy of in the detection capacity of internal defects of material to be detected, by keeping apparent dimensions of ultrasonic vibrators almost constant as viewed from the material being detected regardless of the angle of refraction of an ultrasonic beam. CONSTITUTION:When emitted with the ultrasonic beam deflection angle theta from ultrasonic vibrators 2l-2m located almost at the center of an array type probe, an ultrasonic beam 3 is refracted on the boundary 8 between a shoe 9 and material 4 to be detected to propagate through the material 4 being detected at the angle theta of refraction. At this point, when the wedge angle of the shoe 9 set at alpha, the angle of incidence of the ultrasonic beam emitted to the shoe 9 at the angle theta of deflection with respect to the boundary plane is given by alpha=phi+gamma. Thus, a signal controller calculates the delay time in the transmission and reception when ultrasonic waves are each transmitted and received by the vibrators 2 at each deflection scan angle of the ultrasonic beam to set transmission and reception delay data to a transmission/reception setter each time the scan angle is altered. Therefore, the transmission and the reception of the ultrasonic beam can be done at a specified angle of refraction, thereby enabling the detection kept of flaws with the beam 3 to the material 4 being detected constant in the thickness.
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