| 摘要 |
PURPOSE:To perform flaw detection automatically and accurately as to corrosion nearby the skirt base part of a cylinder by correcting sensitivity of the echo intensity of a main probe, cylinder by cylinder, with the received wave of an auxiliary probe which is received by cylinders. CONSTITUTION:The main probe 6a and auxiliary probe 6b are arranged inside and outside the skirt 2 of the cylinder 1 nearby the cylinder 1. While the cylinder 1 is rotated by a rotary driving roller 9, flaw detection is performed as to corrosion in a flaw detection area inside the skirt 2. The surface roughness and curvature of a bottom surface which vary according to the kind of the cylinder 1 affect how easy the ultrasonic wave from the main probe 6a enters a plate, so the ultrasonic wave sent by the main probe 6a is received by the auxiliary probe 6b, cylinder by cylinder and a sensitivity correction processing block 10 corrects the sensitivity of the echo intensity of the ultrasonic wave which is sent by the main probe 6a and reflected by the corrosion part, cylinder by cylinder. The sensitivity-corrected echo intensity is calculated by a corrosion state calculation processing block 11 specifically and a normal/abnormal decision processing block 12 makes a normal/abnormal decision.
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