BENEFICIAL EFFECTS OF THE ADDITION OF SOYA BEAN OIL ON THE TENSILE STRENGTH OF EXPENDABLE CORES BONDED WITH NIGERIAN GUM ARABIC.

Abstract

Varied quantities of soya beans oil was mixed with each of the four commercial grades of Nigerian gum Arabic and used to bind foundry core sand. The cores were subjected to tensile strength tests after oven baking at 200°C for 1-3 hours to ascertain the benefits of soya beans oil presence over cores bonded with plain gum Arabic already studied in previous works [1, 2, 3, 4]. Experimental test specimens made with silica base sand were shaped like the figure number eight. A standard universal strength machine equipped with specimen attachments and meter to read tensile strength instantaneously was used in foundry laboratory of Ajaokuta Steel Company Limited, Nigeria. The research result showed that soya beans oil addition to gum Arabic bonded cores has beneficial effects on cores bonded with grades 1, 2 and 3 Nigerian gum Arabic as it improved tensile strength by averages of 10%, 7%, and ±2% respectively. It however depressed the tensile strength of grade 4 gum Arabic bonded cores by 2-6% depending on baking duration.