| 摘要 |
PURPOSE:To obtain an Al alloy piston excellent in heat-resisting crack property by performing a specific heat treatment after conducting internal chill casting the iron material ring carrier, surface thereof is Al-Fin treated, by Al alloy of Al-Si-Cu-Mg specific composition. CONSTITUTION:Iron material ring carrier 4, surface thereof is Al-Fin treated, is placed upon a specific position of the die 3 for casting piston which is consisted of the cope 1 and the drag 2. A molten metal is poured into the die 3, and the ring carrier 4 is made into a unitary body by Al alloy thru internal chill casting procedure, wherein the molten metal is consisted of Si 8-20%, Cu 0.5-4%, Mg 0.5-1.5% and the rest is substantially Al. After the above procedure, the body is heated for 1-8 hours under the temp. 480-520 deg.C, followed by the heat-treatment by exposing it in the atmospheric teml. or by oil-cooling. This method prevents the separation of Al alloy from the ring carrier, and enables remarkable improvement of heat-resisting crack property. |
