Effect of Tin as Alloying Element on Grey Iron Automobile Casting

Abstract

Engine castings are made in grey iron which has UTS (ultimate tensile strength)around 250 MPa. Requirement is to make grey cast iron with higher strength without loosing grey cast iron properties namely thermal conductivity and damping capacity. Objective is to develop high grade cast iron by adding alloying elements. Base iron was made in medium frequency induction furnace. Furnace was charged with medium carbon steel and foundry returns as charge materials. Carbon and silicon percentage in base iron was raised by adding petroleum coke and ferro silicon alloys during melting stage. Hot liquid metal was taken into ladle and alloy tin (Sn) addition had been done into the same metal Alloyed liquid metal was poured into a drys and mould in the bar form. Inoculation (ferrosilicon) had been done before pouring into sample mould. Base grey iron was alloyed with tin in the range 0.010–0.100 wt %.Four numbers (nos.) of test bar samples had been made in the different tin percentage range keeping copper constant in the range 0.45–0.5 wt %. Tin(Sn) was added in grey iron to study mechanical and microstructural properties. Tensile, hardness and impact test had been performed for mechanical properties study. Microstructural properties had been studied on optical microscope for the same tin varied samples. UTS was found upto 253–376.11 MPa, hardness upto 173–222.33 BHN and impact strength upto 3.33–4 J.