| 摘要 |
PURPOSE:To obtain an ultrasonic flaw-detection method for detecting a surface defect such as a crack which is generated and progresses within a steel structure and then measuring the dimensions. CONSTITUTION:An electromagnetic ultrasonic probe 1 for transmission which transmits a transverse wave where the polarization direction is vertical to a planar defect such as a crack is laid out on one surface of a specimen 7 and then a similar electromagnetic ultrasonic probe 2 which receives the transverse wave in the polarization direction is laid out on the other surface. Both probes are connected to transmission/reception terminals of each flaw detector 3. When both probes are scanned and they arrive directly above a planar defect 8, a pulse which is subjected to mode transformation into a surface wave on the defect surface appears at a position which is delayed by a certain amount of time from a pulse arriving through a non-defective part. The time difference is calculated by a signal processor 5, thus measuring the defect width. |
