ULTRASONIC FLAW DETECTING METHOD

摘要

PURPOSE:To detect even an extremely small defect speedily with high precision, by specifying a flaw detection frequency and a flaw detection beam diameter, and scanning a probe with specific step width for flaw detection. CONSTITUTION:The probe 2 is provided over a material 1 to be tested dipped in water and the high-frequency ultrasonic wave beam of 30-100MHz reduced in beam diameter to <=0.3mm. is made incident to the material 1 to be tested through the water by the probe 2. The probe 2 is scanned in an X and a Y direction with <=0.2mm. step width (a) by a scanner controller 3 and the focal depth of the ultrasonic wave beam from the probe 2 is made coincident with a gate range preset depending upon the thickness of the material 1. An ultrasonic flaw detector 4 fetches a reflection echo into a minicomputer 5 at the same collection speed (b) with the step width (a) during the scanning of the probe 2, and only data within the focal depth range are transferred to a main computer 6 after distance and amplitude corrections to be displayed on a graphic display device 7.