American-Eurasian Journal of Scientific Research 4 (2): 97-102, 2009 ISSN 1818-6785 © IDOSI Publications, 2009 Corresponding Author: Nuhu A. Ademoh, Department of Mechanical Engineering, Nigerian Defence Academy, P.M.B 2109, Kaduna, Nigeria 97 Estasbishment of the Beneficial Effects of Addition of Linseed Oil to Foundry Sand Cores Bonded with Nigerian Gum Arabic Grades 2 and 4 Nuhu A. Ademoh Department of Mechanical Engineering, Nigerian Defence Academy, P.M.B 2109, Kaduna, Nigeria Abstract: The effect of addition of linseed oil to Nigerian gum Arabic grades 2 and 4 on baked tensile strength of sand cores used as implants in foundry moulds was studied. Defined quantities of gum Arabic and linseed oil were mixed together and used to bind sand cores that were later baked at 180°C and 200°C and then analysed for tensile strength to establish any property improvements over cores bonded with plain gum Arabic. Core specimens shaped like figure eight in accordance with foundry practice were baked in an electrically powered oven and then tested with a universal strength machine after oven cooling them to room temperature. The research showed that addition of linseed oil to plain grades 2 and 4 Nigerian gum Arabic caused property enhancements. The effects were in the form of increased tensile strength of baked cores of about 12% and reduced baking period of about 1 hour. Permeability and shatter index were marginally reduced by about 3% over cores bonded with plain gum Arabic. values were still within acceptable ranges for core applications. Key words: Linseed oil Gum arabic Cores Effects INTRODUCTION abundant in the country [7]. A research study by Linseed oil is one of the traditional materials used in oils are suitable for binding foundry cores but with each foundry binder for sand cores. It belongs to the group suffering from certain technical limitation. On this basis, classified as drying oils [1]. Gum Arabic is natural resin this study is aimed at combining Nigerian gum Arabic that contains arabin; a semi solidified sticky fluid that with linseed oil to produce high quality core binder to oozes from incisions made on the bark of acacia trees [2]. ease. The objective of this paper is to mix each of grades Gum Arabic was combined with different organic resins to 2 and 4 Nigerian gum Arabic exudates with quantities of produce high quality core binders for foundry uses like imported linseed oil to bind core specimens, analyse addition of 5% of the material to 10% sugar and protein specimens for permeability and tensile strength and in a gelatinous mix derived from amino acid to bind compare result with standard in Table 1 [9] and previous expendable cores for sand casting and combination of it works to ascertain property enhancement over cores made with sugar, urea formaldehyde resin and boric acid to bind with plain single binders. sand cores [3], [4]. Grade 2 Nigerian gum Arabic was used to bind foundry core specimens baked at 180-220°C for Experimental Methodology: The green permeability, 1-3 hours and analysed for properties that proved the shatter index and baked tensile strength of specimens material suitable for different alloys [5]. Grade 4 gum bonded with different blends of each of Nigerian gum Arabic proved suitable for binding expendable cores in Arabic grades 2 and 4 with linseed oil were experimentally another study in a series of researches to find extensive measured with a standard permeability meter, shatter foundry uses for Nigerian gum Arabic [6]. machine and universal strength test machine using normal Nigerian foundries including those of the integrated procedures of foundry laboratory. These properties steel plants at Ajaokuta and Aladja depend on imported critically determine ability of cores to withstand interior core binders like linseed oil due inadequate research on thermal stresses imposed on them and to enable them the potentials of local materials like gum Arabic that is allow easy exit of the evolved gasses during casting for Aponbiede [8] revealed that some indigenous vegetable