As-cast Microstructures of 356 Aluminum Alloy Cast by LSC

The as cast microstructures of 356 alloy cast by liquidus semi continuous casting (LSC) were studied. When the billet is cast from the normal casting temperature (720?℃), the border and the center microstructures are coarse, dendritic and asymmetry greatly. When the billet is cast upper the liquidus temperature (625?℃) and the melt alloy is held for 30?min, the border microstructures are small dendrites. The border microstructures are net spherical grains. When the billet is cast from the temperature (615?℃) close to the liquidus and the melt alloy is held for 30?min, the border and the center microstructures are the best and there is a little difference between them, but the grains are fine, uniform and globular. The average diameters of the grains are about 25～35?μm and the average circularity is about 1 75～2. In addition, the reduction of the first cooling and the casting velocity,the enhancement of the second cooling are propitious to the formation of the fine, uniform and globular grains.