| 摘要 |
PROBLEM TO BE SOLVED: To manufacture a pipe free from any defective welding and with high circularity by correctly butting both ends of a workpiece to each other in a tightly attached manner when performing the butt welding of both ends of the workpiece bent in a cylindrical shape. SOLUTION: One end in the circumferential direction of a workpiece W attached to a mandrel 2 is pressed against a center plate 16, and its one end is slightly pressed against a back bar 3 on the mandrel 2. Then, the center plate 16 is lowered, the other end in the circumferential direction of the workpiece W is slightly pressed onto the back bar 3. Successively, the workpiece W is held by two tabs 18 from both sides in the longitudinal direction to correct the deviation of the workpiece W in the axial direction, and the tabs 18 are tightly attached to both ends of the workpiece W. Then, one end of the workpiece W is firmly pressed and fixed onto the back bar 3, a lower end of the workpiece W is pushed up in this state, and both side surfaces of the workpiece W are pressed to butt both ends of the workpiece W to each other without any space therebetween in a tightly attached manner. Then, the other end of the workpiece W is firmly pressed and fixed onto the back bar 3, and finally, the butted parts of the workpiece W are subjected to the butt welding. COPYRIGHT: (C)2009,JPO&INPIT |
