ULTRASONIC FLAW DETECTING METHOD FOR SOCKET WELDING COUPLING

摘要

PURPOSE:To allow flaw detection over a wide range while enhancing S/N ratio by comparing a positional signal of an oblique angle probe detected by a position detecting means while driving a rotating means with an electric signal produced from an oscillator receiving ultrasonic wave reflected on a defect at a welded part. CONSTITUTION:When a welded part 14b between a piping 14 and a joint member 14a is inspected, a clamp arm 58 is adjusted to clamp the joint 14a in the vicinity thereof thus securing an apparatus 10 to the piping 14. A rotary board 17 is rotated by a motor 23 while applying the under face of an oblique angle probe to the joint 14a and then the probe 13 is shifted along the outer peripheral face of the joint 14a thus carrying out the inspection. When the probe 13 is being shifted, ultrasonic wave is transmitted from a transmission oscillator 54 through a transmission side wedge 53 toward a flaw detecting part. An echo reflected on a defective part 14c propagates through the piping 14 and a receiving side wedge 55 to a receiving oscillator 56 where the amplitude of defect echo is detected. Positional signal of the probe 13 detected by the encoder 24 is then compared with a signal received by the oscillator 56.