Department of Agricultural and Environmental Resource Engineering, University of Maiduguri, Borno State, Nigeria

Abstract

Austempering heat treatment is a proven way of obtaining the desired microstructure for improved mechanical properties. It is an isothermal heat treatment process in which an attractive combination of mechanical properties of austempered ductile iron (ADI) may be produced. In this paper, a statistical model for the determination of some mechanical properties was developed. The ductile cast iron was annealed after which it was austennitized at 850 and 950 °C. After the austenitizing process, it was then austempered in hot jatropha seed oil. The developed prediction model was then utilized to assess the tensile strength and hardness of the ADI. The result of the austempering process showed appreciable improvement in tensile and hardness values measured.  Optimum values of tensile and hardness were 962 kN/mm² and 405 BHN respectively. Values of 961.4N/mm² and 340.1BHN were obtained using the developed model. It can therefore be concluded that, the closeness in the values obtained from the experimental measurement and the prediction model is an indication of the effectiveness of the developed model.