Feasibility Study of Stone-Dust as an Alternative Material to Silica Sand for Al–Si (A356) Alloy Casting

The present investigation focuses on the development of metal casting mold using stone-dust as an alternative mold material to silica sand. The stone-dust aggregate mold having 4 wt.% of moisture and 11 wt.% of bentonite clay shows desired mold properties as per AFS standard. The mold properties such as permeability number, hardness (B-scale), compressive, and shear strength are 147, 88, 1.48, and 0.33 kgf/cm2, respectively. The fusion point of stone-dust is found to be below 1350 °C and phase changes are observed above 1000 °C. Hence, the stone-dust mold is suitable for Al alloy casting. Therefore, a laboratory-scale casting trial is taken to cast A356 alloy using green stone-dust and silica sand mold. The hardness (HRB), as cast surface roughness (Ra) and microstructure of silica sand and stone-dust mold casting are evaluated and compared. It is observed that stone-dust mold shows higher hardness as compared to silica sand mold. Hence, stone dust mold may be used as an alternative to silica sand in Indian foundries for aluminum alloys casting.