| 摘要 |
PROBLEM TO BE SOLVED: To obtain an evaluation methods in which the size of a defect can be evaluated precisely even regarding a spherical defect which is larger than the width of a beam by a method wherein an ultrasonic probe is scanned and the scale of the defect is evaluated on the basis of the distance between peaks in the intensity distribution of reflected waves. SOLUTION: When an ultrasonic array probe 1 is scanned in the X-direction, the center line 4 of a focused beam at an angle of -θ is passed through the center pi of a defect on the left side of a perpendicular line N when it comes to a position A. At this time, an ultrasonic beam perpendicularly hits the outside of the defect 10, and the intensity of reflected waves indicates an intensity distribution in which a peak is situated in the scanning position A. In addition, the center line 5 of a beam at an angle of θ. is passed through the center p1 of the defect 10 on the right side of the perpendicular line N. At this time, the beam perpendicularly hits the outside of the defect 10, the intensity distribution of reflected waves becomes a peak in a position A', and the distance between peaks becomes X1 . On the other hand, in a large defect 20, the distance B-B' between peaks in the intensitity distribution of reflected waves becomes X2 . Naturally, X1 (X2 , the distance between the peaks is changed according to the size of a defect, and the size of the defect can be estimated. |
