| 摘要 |
PURPOSE:To obtain a wheel made of an Al-alloy having high strength and high toughness, by subjecting a molten Al-alloy having a specific composition of which the Fe-content is especially enhanced to high pressure casting molding in a mold while applying heat treatment to the molded alloy. CONSTITUTION:An Al-alloy consisting of on a wt. basis, 6-8% Si, 0.15-0.30% Mg, 0.20-0.50% Fe, 0.2% or less Cu, 0.3% or less Mn, 0.2% or less Ti and the remainder substantially Al is used and pressure of 200kg/cm<2> or more is loaded to the melt of this Al-alloy in a mold to perform casting molding. Subsequently, T6 heat treatment for performing ageing treatment at 150 deg.CX5H after solution- heat treatment at 535 deg.CX9H is applied to the molded one. By this method, a coagulation speed during casting is accelerated to make it possible to make a cast coagulated structure fine so as to reduce the dendrite size thereof to 20mum and a wheel made of the Al-alloy excellent in strength and toughness is obtained.
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