| 摘要 |
PURPOSE:To improve the adhering property of external fins under a high temperature by a method wherein axial internal fins are formed by the extrusion forming of aluminum and external fins of aluminum, which are rimmed at the inside thereof, are welded to the external surface of the main frame of the heat exchanger by pressure. CONSTITUTION:The main frame 8 of the heat exchanger, equipped with a plura- lity of axial internal fins 7, is formed by the extrusion forming of aluminum. The external fins 10, formed by pressing an aluminum plate so as to have the rimmed part 9 having the internal diameter smaller than the external diameter of the main frame 8 of the heat exchanger at the inside thereof, are adhered and secured to the outer periphery of the main frame 8 of the heat exchanger by pressure welding work. |
