WEAR-RESISTANT ALUMINUM ALLOY FOR CASTING ENGINE BLOCKS WITHLINERLESS CYLINDERS

摘要

An aluminum-silicon alloy composition is disclosed which meets the manufa cturing and performance conditions for linerless cylinder engine block casti ng using low-cost casting processes such as silica-sand molds. The alloy of the invention comprises in weight percent: 13% - 14% Si; 2.3% - 2.7% Cu; 0.1 % - 0.4% Fe; 0.1% - 0.45% Mn; 0.1% - 0.30% Mg; 0.1% - 0.6% Zn; 0.05% - 0.11% Ti; 0.4% - 0.8% Ni; 0.01% - 0.09% Sr; and and the rest being aluminum plus any remainders. This alloy has very good machining characteristics, giving a significantly improved surface finish in the cylinder bores. The manufactur ing cost of engine blocks is reduced in about 40% as compared with using cur rent commercial alloys of the prior art requiring iron liners. Any primary S i present is substantially uniformly dispersed, and copper does not segregat e during solidification and cooling.