| 摘要 |
PURPOSE:To perform the accurate flaw detection of a welded part, by transmitting ultrasonic waves obtained by successively delaying the phase determined by the outer diameter, wall thickness and desired angle of refraction of a steel pipe and adjusting the deflection angle of ultrasonic waves from the sonic wave distribution of reflection so as to reduce scattering. CONSTITUTION:A transmitting array type probe 10 and a receiving array type probe 10' are arranged in a left and right symmetric state and an ultrasonic wave is received by the probe 10 and the ultrasonic wave reflected in a steel pipe 20 is received by the probe 10' to detect the sound field distribution of the ultrasonic waves. If the angle of refraction of the ultrasonic wave in the steel pipe 20 is constant, because the scattering of the ultrasonic wave reflected in the steel pipe is reduced, the sound field distribution of the ultrasonic wave received by the probe 10' comes to a drawing (b) and, if the angle of refration is not constant, the scattering of the reflected ultrasonic wave increases and, therefore, the sound field distribution comes to a drawing (c). Pulse voltage obtained by successively delaying the phase determined by the outer diameter, wall thickness and desired angle of refraction of the steel pipe is applied to the probe 10 and, with respect to the generated ultrasonic wave with an angle alpha of deflection, an angle of deflection is shaked before and after said ultrasonic wave to transmit the ultrasonic wave and the angle of deflection, that is, phase delay quantity is adjusted so that the received sound field distribution becomes the drawing (b).
|
