| 摘要 |
PURPOSE:To improve the productivity by finding the torsion rate of a welded part by a specific equation based on detect signals of welded part detectors installed to both ends of a steel pipe, and then, performing flaw detection along the distorted welded line of the steel pipe. CONSTITUTION:Electromagnetic sensors 7 and 7' of welded part detectors are put on the welded seam 15 of both ends of an electric welded tube 1 turned by the roller of a turning device (both are not shown in diagram) and the welded seam line 15 at both ends is detected. Then the torsion of the tube 1 is found from a specific formula using the pulse difference dp of seam signals obtained from the sensors 7 and 7' and the outer diameter D and length L of the steel tube 1. After the torsion is obtained, a supersonic flaw detecting terminal mechanism section 12 is run along the estimated linear seam line 14 while the mechanism section 12 is driven and controlled by a torsion follow-up motor 13 based on the torsion found from the specific formula. Thus the flaw detection of the steel tube is performed. When such system is used, highly reliable flaw detection can be performed on the welded part and its vicinity utilizing supersonic waves. |
