| 摘要 |
PURPOSE:To achieve a simpler and smaller inspector, by making an ultrasonic beam emitted from an ultrasonic probe hit material to be detected vertically to detect inclusion of the material being detected from the attenuation of the bottom reflected wave from the back thereof. CONSTITUTION:A water jet nozzle 3-1 containing a focus type ultrasonic probe 2 and another one 3-2 without the probe 2 are arranged at the position facing each other to sandwich a thin steel hoop 1 as material to be detected. When an ultrasonic beam 4 is emitted from the probe to hit the surface of the steel hoop 1 vertically through a water column of a water jet, it is mostly reflected to be a surface echo S while a part thereof is transmitted through the thin steel hoop 1 and reflected on inclusion 6 and the bottom to be defect echoes F1-F3 and bottom echoes B1-Bn. Thus, detection can be done accurately and easily with a simple construction even when the inclusion 6 in the thin steel hoop 1 is very minute.
|
