Experimental Analysis of Mechanical Properties, Wear and Corrosion Characteristics of IS400/12 Grade Ductile Iron Casting

Abstract

In the present research investigation, ductile iron castings conforming to IS400/12 grade casting were produced using green sand moulds. The castings were produced in a regular production foundry using 1.25T Induction Furnace. The molten metal was subjected to standard desulphurisation and modularisation to get graphite in the nodular form. The molten metal was poured into the sand mould and allowed to solidify. test was held for different loads viz. 300 gm, 400 gm and 500 gm and different speeds conditions viz. 950 r.p.m, 1430 r.p.m and 2130 r.p.m Based on the earlier investigation by the above group the castings were austenitised at 900 o C for 120minutes and quenched in a salt bath consisting of potassium nitrate and sodium nitrate in the ratio of 55:45 and maintained at 310 o C for 120 minutes to bring about austempering treatment. The result in austempered ductile iron will consist of graphite nodules in a matrix of bainite[1,2]. The effect of austempering heat treatment on microstructure, mechanical properties and wear characteristics were studied and compared with the ascast condition. Mechanical properties such as ultimate tensile strength, percentage elongation, hardness and impact strength were determined. Wear tests were carried out to determine the weight loss of specimens; using pin on disc type machine. Wear . The results of the research investigation indicate that the heat treated castings shows higher Ultimate Tensile Setength values (35.93% increase), elongation values (24.2% increase) and Brinell hardness values (12.05% increases) as compared to the as-cast condition of casting. From the dry sliding wear studies, it is seen that heat treated specimensshows higher resistance to wear compared to the ascast specimens.