Master Cooling Curves of Cooling Curves on Moulding

The following expression was assumed among the cooling time of liquid metal in mold t, the representative size of molding D, the ratio of volume and surface area of molding V/S, and specific heat s. t=k(D･W/S)^n･.c^^n' (k : proportinal constant) The values of n and n' were calculated for many experimental cooling curves of solder, zinc, lead and tin. From the results of calculation, these values could be obtained n=0.953 and n'=0.418 respectively. By use of these values, the experimental cooling curves were normalized for each factor. These normalized curves were very much agreement, so the master cooling curves in solidification of liquid metal could be obtained. For the normalization of cooling curves in mold, the following expression was assumed too. x=kt^n (k : proportinal constant) Where x is the distance from the boundary between mold and molding, t is the cooling time and n is an experimental constant. The values of n, based on many experimental cooling curves, was 0.508. The master cooling curves of mold can be obtained, when applying the values of n to experimental curves.