An Austempering Study of Ductile Iron and the Effect of Copper Addition on the Tensile Properties of Austempered Ductile Iron

Abstract

Austempered Ductile Iron (ADI) has proved to be an excellent material as it possesses attractive properties like high strength, ductility and toughness combined with good wear resistance and machinability. These properties can be achieved upon adequate heat treatment which yields optimum microstructure for a given chemical composition. In this work, an investigation has been conducted on ductile iron alloyed with Cu and austempered in a range of time and temperatures. The influence of austempering temperature, time and copper addition on tensile strength and elongation of ADI has been determined. The tensile strength was found to increase with decreasing austempering temperature, with maximum tensile strength seen in samples austempered at lower temperature, 250 °C, and for shorter time. Maximum ductility was obtained after austempering for 1.5 h. An increase in the ductility of ADI was found on copper addition.