AUTOMATIC SENSITIVITY CALIBRATING METHOD OF ULTRASONIC FLAW DETECTOR FOR WELDED PIPE

摘要

PURPOSE:To correct the sensitivity of a probe for thick center part defect detection automatically by setting a defective gate on the basis of comparative defects provided to a comparative test-piece at a specific position, and moving the test-piece and a probe group relatively. CONSTITUTION:Comparative defects 6a-6c are formed with a drill, etc., at distances of a 0.25 skip, etc., circumferentially from the weld line 2 of the comparative test-piece 1 and on the weld line 2. Those defects are utilized to set the defect gate of the probe 3C for thin center part defect detection. Then, the test- piece 1 and probe 3C move substantially relatively and the probe 3C functions similarly to internal and external surface defect detectors 3A and 3B and the sensitivity of the detector 3C is corrected automatically similarly to the detectors 3A and 3B.