| 摘要 |
PROBLEM TO BE SOLVED: To measure precisely the defect length of a transverse crack of a weld zone by using ultrasonic flaw detection. SOLUTION: A pair of longitudinal wave angle probes 11, 12 are arranged across a weld line 13 between parent metals 15, 16 of a measuring object 10. The longitudinal wave angle probes 11, 12 are arranged in such a state that the line connecting respective probes 11, 12 is tilted at 45 deg. relative to the weld direction 14 of the weld line 13. When the longitudinal wave angle probes 11, 12 are moved in parallel with the scanning direction 18 parallel to the weld direction 14, a defect echo shown by the figure (b) is obtained. As the defect echo length, 22 mm can be obtained from a reference value 25% of the defect echo height determined beforehand by a test piece or the like. The length of a transverse crack 17 at that time is 21 mm, therefore, the defect length can be obtained precisely. |
