| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method of an aluminum-made downpipe capable of simply applying corrosion-proof treatment consisting of an anode oxidation coat to both surfaces of the circumferential surface and the inner circumferential surface. SOLUTION: Fitting means are respectively provided to both side end edges in parallel with the longitudinal direction, a pair of longer divided downpipes 2a and 2b formed in a cylindrical-shape by unifying them with the fitting means are formed by extrusion-molding of aluminum or aluminum alloy, and after the anode oxidation treatment has been applied to both divided downpipes 2a and 2b in a divided state to form the anode oxidation coat on each circumferential surface, both divided downpipes 2a and 2b are unified by the fitting means to from it into the cylindrical-shape. COPYRIGHT: (C)2006,JPO&NCIPI
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