METHOD AND DEVICE FOR X-RAY FLAW DETECTION OF WELDING SEAM OF LARGE-DIAMETER STEEL TUBE

摘要

PURPOSE:To improve the degree of defect discrimination of the large-diameter steel tube by providing plural sets of X-ray film carriages on an upward/downward movable long-sized boom inserted into the internal surface of the steel tube so that they can run, and elevating or lowering an X-ray film into contact with the internal surface of the steel tube. CONSTITUTION:A boom cylinder 8 is closed after the large-diameter steel tube 1 is conveyed by a conveyor roller 2 to a specific position determined from the necessary range of X-ray flaw detection, and an elevation screw 9 and the boom cylinder 8 are elevated simultaneously to put the long-sized boom 3 closer to the upper part position of the top surface of the steel tube 1. At the same time, the X-ray film 5 placed on the X-ray film carriage mounted on the long-sized boom 3 is elevated to specific height. The X-ray film carriage moves on rails 24 on the long-sized boom 3 to perform flaw detection to the overall length, and a film mat frame 12 and a mat 4 with elasticity are elevated and lowered to bright the X-ray film 5 into contact with the internal surface of the steel tube.