| 摘要 |
PURPOSE:To join securely an aluminum fin to an iron pipe and to produce inexpensively the finned pipe by forming a spiral hollow groove on the surface of the iron pipe, winding the fin thereon so as to fit the same into the hollow groove and brazing both in a furnace. CONSTITUTION:A steel pipe or an iron alloy pipe is used as an iron pipe 1 and is pretreated by a chemical treatment or mechanical treatment. A hollow groove 2 is formed by using a universal tool. A brazing sheet consisting of a brazing material layer clad on at least one surface of a thin aluminum sheet is used as an aluminum fin material 3. An aluminum-silicon or aluminum-silicon-magnesium material is used for the brazing material layer. A wire-like brazing material is wound between the pipe 1 and the spiral fin 3 in the case of using a single material such as pure aluminum or aluminum-manganese alloy as the aluminum fin material. A mixture composed of a flux for an aluminum alloy as well as zinc chloride, tin chloride and water is used as the flux and the brazing in furnace is accomplished in accordance with a conventional method. |
