Computation of Solidification Time of Copper in Cast Iron Semi-Infinite Mold Considering Imperfect Contact Between Casting and Mold

摘要

Solidification of plate shaped casting of copper in cast iron mold has been modeled considering imperfect contact between mold and casting using explicit finite difference method. For any system there is always a critical mold thickness above which the mold thickness has no effect on solidification time. This critical mold thickness is the semi-infinite mold thickness. The effects of interfacial heat transfer coefficient, superheat of molten metal, initial mold temperature and casting thickness on the solidification time have been analyzed for the semi-infinite mold model. It is found that for plate shaped copper casting, for any combination of casting variables, solidification time makes a rectangular hyperbolic function with inerfacial heat transfer coefficient. Two empirical relationships (exponential and linear) have been proposed for the relation among solidification time, interfacial heat transfer coefficient, superheat of molten metal, initial mold temperature and casting thickness forplateshaped copper casting in semi-infinite cast iron mold. Both of them consist of two parts-parabolic part and nearly linear part. The parabolic part is for perfect contact and the second part is the additional part due to imperfect contact. For perfect contact, the square root of solidification time increases with the increase of casting thickness, superheat and initial mold temperature. On the other hand, in the second part, the additional solidification time increases with increase of casting thickness, superheat of molten metal and initial mold temperature.