| 摘要 |
PURPOSE:To discriminate areal and volumetric flaws, by performing not only oblique angle flaw detection and vertical flaw detection from the part above a weld bead but also oblique angle flaw detection performing oscillation from both sides across the bead and performing evaluation relating to a flaw at every flaw indication position. CONSTITUTION:The guide rod 5 supporting the moving bed 4 to which a probe holder 3 having an oscillating mechanism is specially provided, and screw rods 12 and guide rods 11 allowing a support stand 8 to slide are arranged in parallel to the welding wire of the welded part 2 of a welded pipe 1. The movement of a probe 3 is controlled by a scanning controller 22 and the transmission of an ultrasonic pulse is controlled by a flaw detector 23. The echo from the welded pipe 1 is taken in CPU 21 from the flaw detector 23. CPU 21 detects a flaw indication length at an oscillation angle of 90 deg., the echo height variation pattern at the time of left-and-right scanning, the changed in the max. echo due to the oscillation angle, the echo wave-form at the time of the max. echo height at each oscillation angle and the echo heights at the times of vertical and oblique angle flaw detections above a bead, and performs the operations and weighting of each parameter value to make it possible to discriminate areal and volumetric flaws.
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