| 摘要 |
PURPOSE:To form perfect film without pinhole and to make easy the fitting of an Al fin, by a method wherein a pipe is formed by an Al, Cu composite pipe which is made by forming an Al coating layer by the aluminum press on a Cu pipe. CONSTITUTION:An Al layer 2 is extruded and covered by the aluminum press on a Cu pipe 1 which is manufactured beforehand. Thereafter, the draw reducing process for reducing diameter is performed on a double pipe made of Al and Cu using a die or roll, and a composed pipe of a prescribed inner diameter and outer diameter is manufactured. Since this is the composed pipe having the Al layer 2 on the outer periphery and the Cu pipe 1 inside, it is possible not only to prevent chemical combination of working liquid-water with Al, there is no pinhole at all, and connection can be conducted in the terminal process at the part of Cu pipe. Since outer surface is Al, attaching of Al fins for heat exchange is easy as well as pipes become light weight. |
