ULTRASONIC FLAW DETECTION METHOD OF STEEL PIPE WELD ZONES

摘要

PURPOSE:To enable defect positions as well as presence or not of harmfulness to be judged by displaying the echo height of each division in a Braun tube through the use of a perpendicular flaw detection method and plural division of the thickness of the weld zone and outputting defect echo heights as numerical values. CONSTITUTION:With a hold 4 being placed so as to put on the weld zone 2 of a steel pipe 1, a probe 3 is positioned right above the weld zone and is scanned while water is being supplied from a water supply hole 5. As a result, the position being detected is displayed as axial distance with the pipe end as a reference on a position display device 8 and at the same time the echo height is also displayed in the Braun tube of a flaw detector 10. When a defect echo exists in the 10 channel gate circuit having been set in the weld zone in sychronization to the position signal of the probe, the echo height is converted to numerical values in 10% unit and the numerical eche heights above the preset level and their positions are simultaneously printed and recorded by a printer 12.