| 摘要 |
PROBLEM TO BE SOLVED: To produce an automobile wheel having a designed face high in brightness. SOLUTION: The molten metal of an aluminum alloy contg. 7 to 12% Si, 0.1 to 0.4% Mg, 0.3 to 0.6% Fe and 0.2 to 0.5% Mn is subjected to degassing and deslagging treatment, is thereafter subjected to die casting and is subjected to machining for securing dimensional accuracy after T6 treatment. A surface chilled layer in the wheel designed face is subjected to buffing to impart gloss to the chilled layer, which is formed into a designed decorative face, and moreover, the surface is applied with transparent clear coating. It is preferable that its structure is formed into the one in which, as for the chilled layer in the designed face after T6 treatment, the average grain size of eutectic Si is regulated to <=6μm and the average area ratio of eutectic Si to the matrix is regulated to >=18%.
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