한국주조공학회

The equipment for the horizontal continuous casting was built to produce hyper-eutectic Al-Si bars with a small cross-section of 25mm in diameter. The manufacturing processes including withdrawal cycle and secondary cooling methods were modified to refine the primary and the eutectic Si. The longitudinal casting speeds varied over the ranges of 670-1100mm/min for pure Al, and 200- 350mm/min for Al-17wt%Si alloy. Due to the difference of cooling rate in the mould, microstructural asymmetry between the lower and the upper part of bar was observed. Thus, manufacturing processes such as cooling and withdrawal method were optimally combinated to get the homogeneous cast structure. With the increase of casting speed, the primary Si size was refined down to 30μм near the surface, and 80μм in the center of the bar.