| 摘要 |
PURPOSE:To shorten a dead zone, to obtain high resolution, and to improve the defect detection precision of a water dipping flaw detecting method by using a metallic material which is fast in acoustic velocity and reducing the thickness of the lens. CONSTITUTION:An oscillator 1 oscillates acoustically with electric pulses from a plug 2, but its free oscillations are suppressed by the backing material 3 on the back surface and the steel-made acoustic lens 4 to transmit an ultrasonic wave narrow pulse width. In this case, the backing material 3 uses resin with which heavy metal powder of tungsten, etc., is mixed to suppress the free oscillation effectively, and the thickness of the center part of the steel-made a coustic lens 4 is a quarter as large as the wavelength of the ultrasonic wave so as to suppress the free oscillations effectively. Consequently, noise echoes due to the multiple reflection of the ultrasonic wave by the lens are reduced to shorten the dead zone, obtaining a high-resolution probe having narrow pulse width. |
