| 摘要 |
PURPOSE:To prevent the production of a noise echo and to enable to perform a detection of flaw with a preferable SN ratio, by a method wherein a diameter of a water columnar hole is made larger than that of an ultrasonic vibrator, defoaming grooves are formed in a probing hole connected to the water columnar hole, and water feed holes connected to a water port are provided in the proximity of the end of the probing hole side. CONSTITUTION:A water columnar hole 6 is formed in a diameter larger than that of an ultrasonic vibrator 13, blister grooves 14 are formed in a probing hole 4 and in 3 spots in the peripheral direction of the probing hole 4 so that they pass all the way through a probing shoe to its upper surface. When finding a flaw, water is fed so that a water level in the grooves 14 exceeds the surface of the ultrasonic vibrator. Water feed holes 5, linked to a water port, are formed in the end of the probing hole 4 side in the water columnar hole 6. Water is normally stably supplied into the water columnar hole 6, and the surface of the ultrasonic vibrator 13 is kept prevented from being out of water, and air bubbles in the water column 5, produced due to some cause, is rapidly removed through the defoaming holes 14. Additionally, the water column 5 is formed in a diameter larger than that of the ultrasonic vibrator 13, and this allows to obtain a high sensitivity. |
