A novel material used in automotive industry: compacted graphite iron

Abstract

In recent decades, materials have been a key to increase the performance of automotive parts which leads to development of new materials. The main objective is to achieve increase in quantity and quality of automotive parts produced with optimum performance during their life cycle. Cast iron has remained a competitive material due, in part, to its low production cost. In fact, among the cast iron group, one of the alternatives is lightweight alloys, that is, compacted graphite iron (CGI). Nowadays, it is accepted that CGI can effectively reduce the total weight of an automobile by virtue of its high strength- when compared to other cast irons and aluminum alloys. The paper presents a comparative view of CGI with gray cast iron and ductile iron. Surface morphology has been studied by scanning electron microscopy. Tensile strength and other properties have been calculated by stress-strain curves. Hardness has been measured by Brinell hardness testing methods. Several metallurgical variables need to be strictly controlled in order to achieve consistent CGI properties in a production line at reasonable costs for the automotive industry with at least 75% higher tensile strength, 45% higher stiffness and approximately double the fatigue strength of conventional grey cast iron.