EFFECTS OF VARIATION OF BAKING TEMPERATURE AND TIME ON TENSILE STRENGTH OF FOUNDRY SAND CORES BONDED WITH NIGERIAN GUM ARABIC
Publication Date : 01/08/2010
The effect of temperature at which cores bonded with Nigerian gum Arabic are baked on foundry properties was investigated in this study. The four grades of gum Arabic produced in commercial quantities in Nigeria were separately used to bind foundry sand core specimens. The specimens were grouped, oven baked at temperatures of 160°C, 180°C, 200°C, 220°C and 250°C for periods ranging from 1 to 3 hours, oven cooled and then tasted for baked tensile strength using a standard universal strength machine. Each test core was made of 4.5% of each grade of Nigerian gum Arabic exudates, 3% moisture and 92.5% silica sand grain. The test data was analysed to ascertain the effects of varied baking treatments on tensile strength and the optimal processing periods of such cores. The results revealed that the optimum baking temperature and time for grade 1 gum Arabic bonded cores were 220°C and 2.5 hours respectively. The optimum baking temperature and period for grade 2 gum Arabic bonded cores were 220°C and 2.5 hours; those for grade 3 gum Arabic bonded cores were 200°C and 2.0-2.5 hours; while those for grade 4 gum Arabic bonded cores were 200°C and 2.5 hours respectively.
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