Static solid cooling: A new directional solidification technique

Abstract

A new directional solidification technique has been presented. This technique employs the pyrolytic graphite for heat dissipation by conduction and does not withdraw the cast. The furnace design was presented for this static solid cooling (SSC) method. A heat dissipation model was put forward for evaluating the cooling efficiency by calculating the total thermal resistance in directional solidification. The total thermal resistance in the SSC method is the minimum compared with other methods. The solidification process is simulated and the results show that the axial temperature gradient increases to 130 °C/cm from 52 °C/cm (Bridgman method) and the growth rate is improved to 10.84 mm/min from 3.86 mm/min (Bridgman method). The solidification time is reduced by 64.4%. The cooling rate increases dramatically as well. Additionally, the heat insulation of the hot and cool zones is improved substantially in the SSC method. The thermal resistance of the mould is reduced as well due to the thin mould. Besides, the SSC method employs the electrical network to control the growth rate. The solidification condition is much uniform due to the position control by the electrical network.