Chill material and size effects on HTC evolution in sand casting of aluminum alloys

An extensive experimental investigation on the heat transfer coefficient (HTC) during sand casting of aluminum alloy is presented here; the variation in time of the HTC in the whole cooling process was reconstructed with many kinds of chills, different in size and material. Cast iron, aluminum and copper were used as chill materials, the HTC between aluminum and sand also being considered. In particular, typical foundry practice regarding melt treatment, sand preparation and chill manufacturing and assembly within the mold is considered throughout the analysis, in order to obtain the most reliable HTC values. The evaluated HTC are then put in relation with cast and chill temperature, in order to allow the easiest transportability to simulation codes for foundry. Relevant points of HTC curves and physical behaviors of the interfaces are also discussed.