| 摘要 |
PURPOSE:To prevent the intrusion of a welding material into an aluminum pipe and to weld efficiently the pipe, by providing a stepped part on the inside surface of the pipe, inserting a junction pipe between the reinforcing pipe inserted therein and the aluminum pipe and welding the pipes. CONSTITUTION:A sloped stepped part 4c is formed on each of the inside surfaces of both end parts 4a, 4b of a header 4 formed by drawing of a blank material for an aluminum pipe. On the other hand, a projecting line 5a is provided to a part of a reinforcing pipe 5 made of a stainless steel, and part thereof is inserted into the header 4 until it is brought into contact with said part 4c, whereby the pipe 5 is positioned. A junction pipe 6 made of aluminum having the inside diameter coinciding approximately with the outside diameter of the pipe 5 is inserted between the header 4 and the pipe 5. The insertion part of the header 4 and the pipe 6 is welded with an aluminum welding material 7 from the outside. The intrusion of the material 7 into the pipe is prevented and the pipe 5 is positioned easily by the above-mentioned method. |
