| 摘要 |
PURPOSE:To perform precise, secure flaw detection in a desired flaw detection area by using an ultrasnonic wave, and performing oblique flaw detection near the corner at the lower part of a flank which adjoin to the ultrasonic-wave incidence surface of a square steel piece and detecting a corner position. CONSTITUTION:When the point O of incidence of an ultrasonic wave beam S is in the center of the incidence surface, a reflected echo from a corner part is maximum when the ultrasonic wave beam S travels in the center A of curvature of the lower part. This principle is utilized and the oblique flaw detection is performed near the corner part to detect the corner position, and the scnning range and flaw detection gate range of the ultrasonic beam are corrected on the basis of the corner position to perform oblique flaw detection. Thus, the flow derection is performed precisely and securely in the desired flaw detection area. |
