Effect of Cooling Slope Angle on Microstructure of Al-7Si Alloy

Attempts were made to obtain non-dendritic microstructure in Al-7Si alloy by pouring the melt on mild steel cooling slope. The melt was poured into the slope at different angles—15°, 30°, 45° and 60°. The pouring temperatures chosen were 630 °C, 640 °C and 650 °C corresponding to melt superheat of 15 °C, 25 °C and 35 °C. The results indicate that a lowest slope angle of 15o along with superheat of 15 °C leads to microstructure with minimum grain size of 33 μm and shape factor of 0.81. The findings showed that lower slope angles would yield minimum grain size, are in contradiction to earlier studies, which could be related only to the lowest possible superheats used in the present study.