Design and Development of Copper Slag Mold for A-356 Alloy Casting

This paper investigated the effect of copper slag mold material on mold properties such as permeability, hardness, compressive strength, tensile strength, and 3-point bending test, and as-cast properties of A356 alloy. Copper slag mold properties were optimized through response surface methodology (RSM) and found that 5% sodium silicate (by weight) and 18 s CO2 gas passing gives best mold properties such as permeability no. 701, hardness 94 HRB, compressive strength 5.2 kg/cm2, tensile strength 0.72 kg/cm2, and 3-point bending strength 2.88 kg/cm2. The as-cast properties of A356 alloy are found to be surface roughness = 6 +/- 1.2 mu m, hardness = 70 +/- 2(HV), secondary dendrite arm spacing (SDAS) = 33 +/- 1 mu m, and porosity = 2.5 +/- .5%. The fluidity of A-356 alloy in copper slag mold was measured 78 cm. The results revealed that the copper slag mold suits A356 alloy casting. However, its recyclability in the industrial scale casting process and its commercial potential as an alternative to silica sand for non-ferrous foundries must be evaluated.