| 摘要 |
PROBLEM TO BE SOLVED: To inspect the distribution of the nonmetal enclosure present in a cast piece from the surface thereof to a specific depth in a depth direction by scanning a probe on the inclined plane having a specific angle of inclination formed by grinding the surface of the case piece. SOLUTION: When the nonmetal enclosure or air bubble present within a case piece 1 is inspected by a vertical ultrasonic flaw detection method using ultrasonic waves of 10MHz or more, a part of the surface 2 of the case piece 1 is ground to form an inclined plane 3 having a definite angle θ of inclination with respect to the surface 2. A probe is scanned on the inclined plane 3 to perform ultrasonic flaw detection. The angle θ of inclination is appropriately selected within a range of 0.03-0.2 radian (about 1.7-11.5 deg.) corresponding to the purpose of inspection. By this method, a flaw present within the region from the surface of the cast piece 1 to a depth of about 20mm can be inspected by using one inspection surface and inspection labor is reduced and a required time is shortened. By forming an image showing whether a flaw at each measuring point is detected, the distribution of the flaw in a depth direction can be displayed obviously. |
