CASSAVA/GUINEA CORN STARCHES AND SOYBEAN OIL AS CORE BINDERS IN SAND CASTING OF ALUMINIUM SILICON (AL-Si) LLOY
Publication Date : 01/08/2006
The paper looked at the possibility of characterizing and developing core mixture formulations from locally available raw materials and determining the suitability of using the cores in sand castings of non-ferrous metals. Varying compositions of core mixtures were formulated using cassava/guinea corn starches and soybean oil. The proportion of guinea corn and cassava starches in the various core mixtures were varied from 2 to 5% while that of Soya oil from 1 to 3%. Standard laboratory test specimens were produced for each core composition and the following parameters which include permeability, green/dry compression strengths, green/dry shear strengths were determined for each test specimen. Cores with optimum strengths were then selected and used in carrying out practical castings. The results of the laboratory tests showed that for all percentages of oil additions and baking times, the cassava starch mixtures possessed higher strengths than the guinea corn starch mixtures. Also the Soybean oil improves the binding properties of cassava and guinea corn starches. Generally the collapsibility of the cores and surface finish of the castings produced using the cores produced from the starches are satisfactory therefore the use of cassava/cereal starch as core binders in non–ferrous sand casting can be said to be very promising.
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