| 摘要 |
PURPOSE:To prevent the generation of a region not subjected to flaw detection by a simple control treatment without enhancing the accumulation density of a probe array, by successively sending out ultrasonic beams different in refractive angles every time when the probe array is changed over to oscillate the same. CONSTITUTION:A focus delay part 14 has eight delay elements each having a delay amount shown in the size in a longitudinal direction and ultrasonic beams from the probe groups of a probe array 10 are converged in the vicinity of the center O of a tubular body 12 to be inspected. On the other hand, in an argument delay part 16, ultrasonic beams converged in the vicinity of the center O of the tubular body are converged to the focus F1 on an X-axis coming to an eccentric amount d1 by the delay elements increased in the delay amounts thereof. Eight probe groups of the probe array 10 are used as one group and the argument delay parts 16A, 16B,... successively reduced in the delay amounts are successively changed over to perform oscillation for sending out ultrasonic beams B, B2,... of which refractive angles theta1, theta2,... are successively changed. By this method, the generation of a region not subjected to flaw detection is prevented by a simple control treatment. |
