Experimental investigation of the effect of temperature in semisolid casting using cooling slope method

Abstract

In this work, the cooling slope method is employed to produce the A356 feedstock in semisolid processing. This paper discusses the effect of temperature on the final microstructure of A356 aluminum alloy in this method. These temperatures are casting temperature, mold temperature, and cooling slope plate temperature. The dendritic primary phase in the conventionally cast A356 alloy is transformed into a non-dendritic one in ingots cast over a cooling plate at casting temperature of 600 ℃, 615 ℃, 625 ℃, 650 ℃, and 680 ℃, and at condition of using a cooling system or without it. After pouring, the melt which becomes semisolid at the end of the plate is consequently poured into cylindrical steel mold at temperatures of 25 ℃, 200 ℃, and 400 ℃. The cooling slope is adjusted at the angle of 50° with respect to the horizontal plane and 500 mm length. It is found that the pouring, plate, and mold temperatures affect the size and morphology of α-Al phase. The effects of these are 22% decrease on average grain diameter and 8.5% increase on the shape factor at the weakest case. The results illustrated that by modifying the temperature the hardness of the specimens is increased. The results indicated that the highest uniformity with the grain size of ∼88 µm and maximum shape factor of 0.68 are related to pouring and mold temperature of 625 ℃ and 200 ℃, respectively using water cooling system.