METHOD FOR MANUFACTURING LONGITUDINALLY WELDED HELICALLY CORRUGATED METAL TUBING

摘要

PROBLEM TO BE SOLVED: To provide a method by which a tube having a deeper waveform or a smaller pitch is manufactured and the waveform is a uniform shape viewed from the length direction of the tube at this time. SOLUTION: A metallic strip is formed into the longitudinal slit tube and, the longitudinal slit is welded and preferably the waveform is formed with a corrugating tool. The corrugating tool is eccentrically supported and inclined to the axis of the tube and attached to a corrugating head which is rotationally driven in the freely rotatable state and hobbing is performed on the surface of the tube. The metallic strip and the metallic tube which is not yet corrugated is moved toward the front with an drawing apparatus. A 2nd drawing apparatus 8 is engaged with the corrugated tube 7 just behind a corrugating device 6 and the drawing speed of a 2nd drawing apparatus is lower than the advancing speed of the corrugated tube 7 which is produced from the inclination of a corrugating ring and the rotational speed of the corrugating head.