| 摘要 |
PURPOSE:To manufacture an Al-alloy core for heat exchangers having a tubular body excellent in corrosion resistance, by extruding an Al alloy containing specific amounts of Mn, Mg, and Cu into a thick-walled tubular body and by machining the thick-walled outside so as to form fins. CONSTITUTION:The Al alloy containing, by weight, 0.05-0.50% Mn, 0.05-0.30% Mg, and 0.05-0.30% Cu is extruded so as to be formed into a thick-walled flat perforated pipe 2 having plural internal holes 2a. Subsequently, the outside surface of a thick-walled part is practically diagonally notched, leaving spaces in the axial direction, and small pieces between agjacent notches are made to stand so as to be formed into fins, or, machined grooves are vertically cut in the thick-walled part leaving spaces in the axial direction and then fins 3 are formed between adjacent machined grooves. In this way, fins 3 are integrally formed on the outside surface of the tubular body 2 so as to manufacture a heat-exchanger core 1 excellent in corrosion resistance.
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