| 摘要 |
PROBLEM TO BE SOLVED: To obtain a method and an apparatus in which an erroneous detection caused by a liquid is eliminated, and in which a defect detection signal due to a change in the texture of a material to be inspected is not generated, by a method wherein a surface-wave flaw detection and an eddy-current flaw detection are performed simultansously and a cylindrical body is judged. SOLUTION: A water gap is formed between the surface of a surface-wave probe 20 and a rolling roll 110. Then, the surface-wave probe 20 propagates surface waves onto the surface of the rolling roll 110, and it detects a surface defect on the rolling roll 110. In addition, an eddy-current flaw detecting probe 30 generates an eddy current in the rolling roll 110, it detects a change in the flow of the eddy current due to a defect, and it detects a surface defect on the rolling roll 110. Then, the defect detection signal of an ultrasonic flaw detector 22 and the defect detection signal of an eddy-current flaw detector 32, which is delayed by a delay circuit 34, are ANDed by an AND circuit 40, and its output is used as a formal defect signal. As a result, the flaw detection of a cylindrical body can be performed with high accuracy. |
