| 摘要 |
PURPOSE:To inspect a crack-shaped defect of a thin plate efficiently and precisely by a method wherein transmission and reception of an ultrasonic wave are executed between outside array elements of three lines and between the outside array elements of three blocks, and switching is made from one element over to the adjacent element, with (n) array elements as one set. CONSTITUTION:Nine elements in the direction of arrangement of an array are switched over so that a first block 21 to 23, 31 to 33 and 41 to 43, a second block 24 to 26, 34 to 36 and 44 to 46 and a third block 27 to 29, 37 to 39 and 47 to 49 can be selected. Transmission and reception of an ultrasonic wave are executed between the blocks of the elements 21 to 29 and 41 to 49 in the direction Y, and when a defect exists in a thin plate 6, a reflected wave of the ultrasonic wave emitted from the block of 41 to 49 is interrupted by the defect and can not be received by the block of 21 to 29. The transmission and reception of the ultrasonic wave are executed between the blocks of the elements 21 to 23, 31 to 33 and 41 to 43 and 27 to 29, 37 to 39 and 47 to 49 in the direction X, and when the defect exists in the thin plate 6, the reflected wave of the ultrasonic wave emitted from the block of 27 to 29, 37 to 39 and 47 to 49 can not be received by the block of 21 to 23, 31 to 33 and 41 to 43. Switching is made from one element over to the adjacent element and scanning is executed in the direction X of arrangement of the array elements. |
