COMPARATIVE STUDY OF Al-7% Si ALLOY CASTINGS PRODUCED BY `V-PROCESS' AND GREEN SAND MOULDING METHOD

Abstract

This work was undertaken to compare several properties of A-356 alloy (Al-7% Si) castings poured in V-process and green sand moulds. To minimise melting and heat treating variables, all moulds of above alloy were poured at the same temperature and all castings used for a given test were heat treated in the same furnace. The data shows that 'V-process' has excellent dimensional accuracy and high surface finish as compared to that of green sand moulding. High volume porosity was obtained in case of green sand moulding. High hardness (BHN value)and less dendrite arm spacing was obtained in green sand moulding, as compared to that of 'V-process'. Tensile properties varied slightly in both the processes. No significant difference were__ob4ieiaean impact strength between both the processes1. After the heat treatment, the tensile strength % elongation and hardness increases, but the % increase in above stated properties was more in case of green sand moulding as compared to that of V-process.