Effect of electric potential on mould powder behaviour during solidification

Abstract

The effect of electric potential on the solidification behaviour of mould powder has been studied. It has been found that electric potential induces crystallisation and that the depth of the crystallisation area is affected by the immersion depth of the electrodes. The solidified mould powder without electric potential treatment is glass. The electric potential enhanced mobility is responsible for crystallisation. The viscosity–temperature relationship of moulder powder is affected by the microstructure. The electric potential increases the viscosity and break temperature of a mould powder with considerable fluctuation of the measurements in comparison with that without electrical treatment. An electric potential of 25 V increases the break temperature of mould powder form 1370 to 1397 K. The observation is explained by the existing theories.

Keywords:

• Mould powders
• Electric potential
• Viscosity

The author would like to express his gratitude to the Tata Steel management for their support in publishing this work. Dr R. S. Qin and Professor Ken Mills from Imperial College, London are gratefully acknowledged for stimulating discussion and kind help.