| 摘要 |
PURPOSE:To eliminate necessity of shrainkage allowance of a tube at the time of welding and reduce working time remarkably in welding both ends of a long member to a base metal, by rotating a welding machine in the same direction or reverse direction along the weld line of the both ends and performing welding at the same time. CONSTITUTION:For instance, in a shell and tube type heat exchanger having perfectly straight heat transmitting tubes, the heat transmitting tubes and tube plates 5 are kept at a fixed distance. Many straight heat transmitting tubes 1 are positioned between the tube plates 5, 5, and both ends of the heat transmitting tubes 1 are welded to the tube plates 5 respectively. Accordingly, in the method that welds many tubes to the tube plates 5, grooves on both ends of the tubes 1 are conformed and both ends of the tubes 1 are welded simultaneously. In this method, welding is performed rotating the welding machine along the weld line. The welding machine is rotated in the same direction or reverse direction at both ends of the tubes 1. Consequently, it is not necessary to provide shrinkage allowance of the tube due to welding, and defects such as discordance of grooves etc. due to shrinkage of the tube are eliminated. |
