METHOD FOR MEASURING ELECTRO-RESISTANCE WELDED PIPE INNER BEAD GROUND SHAPE

摘要

PURPOSE:To favorably measure inner surface ground shape of an electro- resistance welded pipe even with the deviation of the outline shape from a true circle and in the case having outer ground edge part. CONSTITUTION:The present measuring method for the inner ground shape of an electro-resistance welded pipe 1 ground of a welded part 1a with a bead cutter after welding a butting part along with the pipe axis direction utilizes ultrasonic wave. From the periphery of the electro-resistance welded pipe 1 to be measured, ultrasonic wave is introduced vertically including the welded part 1a and the height of inner reflection echo during scanning in the circumferential direction of the pipe is detected. Then, by multiplying a coefficient by the average value of the echo height in the base metal part, a slice level is set. A wider range than the included range (a) with the height of inner reflection echo below the slice level is defined as shape effect width L. In the inner profile, the shape effect width L is removed to indicate.