A Study on Heat Transfer in Sand Molds

In order to investigate the relationship between the thermal characteristics of the various molds as green sand mold, dry sand mold, mold and shell mold, and the solidification characteristics of molten metal, the thermal analysis of rarious molds and melt were performed. The structure of Al-Castings was a/so observed. Results obtained in this experiment were as follows : 1) The heating rate of the molds was increased in the order of green sand mold, mold, dry sand mold and shell mold, On the other hand the solidification time of the melts was shortened in the order of dry sand mold castings, mold castings, green sand mold castings and shell mold castings. 2) The arrest temperature period in the heating curve of the green sand mold was resulted from the eraporation of moisture contained in mold, which was transfered to the outer side of the mold. 3) The temperature fluctuation of the melt in the shell mold was considered to be resulted from the combution heat of resin contained in the mold. 4) The amounts of heat absorption of the molds were increased in the order of dry sand mold, mold, green sand mold and shell mold. 5) The higher the solidification rate was, the longer was its shrinkage pipe and the finer its grain size.