ULTRASONIC INSPECTION METHOD FOR PIPE

摘要

PURPOSE:To make it possible to detect flaws accurately even if there is a defect at both sides of the longitudinal direction of a pipe by judging the progressing state of the defect at a part to be inspected based on the measured values of the part to be inspected when both auxiliary inspecting parts on both sides of the part to be inspected are not normal. CONSTITUTION:The maximum value of the measured values of the transmitted amount of ultrasonic waves at auxiliary inspecting parts 1b and 1c on both sides of the longitudinal direction of a pipe with respect to a part to be inspected 1a is made to be a reference value. The deviation between the reference value and each measured value is obtained. Whether the inspecting parts 1b and 1c are normal or not is judged based on the changing state of the deviation in the circumferential direction of the pipe. When at least one of both inspecting parts 1b and 1c is not normal, the maximum value among the measured values at the part to be inspected 1a is made to be the reference value, and the deviation between the reference value and each measured value is obtained. Then, the progressing state of a defect in the part to be inspected 1a is judged based on the changing state of the deviation in the circumferential direction of the pipe.