Cooling Rate Investigation and The Influence of Pouring Temperature on Hardness Properties of As–Cast Aluminium Alloys

Abstract

This experiment investigated the cooling curve behavior and the effect of variation pouring temperature on three aluminum alloy by casting process. Three aluminum alloys are Al–1.37Zn–1.19Si, Al–1.66Si–1.35Zn, and Al–2.81Zn–2.6Si derived from melting and alloying a pure aluminum with ADC12 (Al–Si) ingot. Cooling curve recorded from two alloys are Al–1.37Zn–1.19Si and Al–1.66Si–1.35Zn with pouring temperature at 710 oC. Pouring temperatures was varied by three variations that are 710, 760, and 810 oC, while the mold temperature kept constant at 220 oC. The result shows, a freezing range of Al–1.37Zn–1.19Si is 643–348 oC and Al–1.66Si–1.35Zn is 621–401 oC with pouring temperature at 710 oC for both alloys. Then cooling rate obtained for Al–1.37Zn–1.19Si is 55.56 oC/S, and Al–1.66Si–1.35Zn is 30.09 oC/S. The hardness index is increasing first then decrease, with increasing of pouring temperature on Al–1.37Zn–1.19Si and 1.66Si–1.35Zn alloys. While on Al–1.66Si–1.35Zn alloy, the hardness value is improving with increasing of pouring temperature.