| 摘要 |
PROBLEM TO BE SOLVED: To detect a defect with high precision by storing a stress distribution of an impeller under a used condition in an impeller form storage device, and moving a focus of a beam along a part where the highest stress is generated in the stress distribution in a plate-thickness direction. SOLUTION: A sample impeller 1 and a positioner 2 are provided in a water tank 3, and ultrasonic wave generated by an ultrasonic wave generating device 4 is made incident to the impeller 1 through a probe 5. By controlling an arm 6 of a robot with a robot control device 7, a relative position of the probe 5 to the impeller 1 is controlled, to move a to be probed surface. Dimension, positional relation and stress of each part of the impeller 1 after worked into a normal dimension is inputted in advance to an impeller form storage device 8. A detection signal of the echo is analyzed with an ultrasonic echo analysis device 10, and position and size of a defect are stored. In addition, based on them and magnitude of the stress which is stored in the device 8, a parameter which shows significance of the defect is calculated, and displayed on an analysis result display device 11. Here, in parameter σ×a<1/2> , σis the stress of the defective part, and (a) is the size of the defect. |
