Influence of Ingate Thickness and Pouring Temperature on Structure and Fluidity of Cast Hyper-Eutectic Al-18%Si Alloy

Abstract

The flow of molten metal after being poured usually is accompanied by turbulence, splashing, separation of streams near change of sections, branching off and rejoining of streams, changes in melt properties such as density, viscosity, surface tension and the solidification behavior. In this work, the effect of gating design (ingate thickness) and pouring temperature on the microstructure and fluidity of Al-18% Si alloy into sand mold are investigated. Four different ingates thicknesses of 2.5, 3, 3.5 and 4mm are used. The melt charge was poured at three different pouring temperature (680, 670, 660 °C) into the mold. Decreasing the ingate thickness slightly improves the microstructure to be fine and more globular. Decreasing the ingate thickness increases the hardness of all cast samples. Increasing the pouring temperature increases the filling area of cast Al-18% Si alloy for all ingates thicknesses used in this study. To maintain complete filling for pouring temperatures of 670 °C and 660 °C a minimum of 3.5 and 4 mm ingate thicknesses consequentially should be considered.