Machinability of alloy ductile iron and forged 16MnCr5 steel

Abstract

The remarkable mechanical properties of austempered ductile iron (ADI) render ADI as an alternative material for forged steels. On the other hand, the high strength and hardness make the machining of ADI to be challenging. In this study, the ADI is presented as an alternative material to fabricate the ring gear of the two-wheel tractors. A series of experiments were designed to evaluate the machinability of the alloyed ductile iron before the austempering process. 16MnCr5 alloy steel and alloyed ductile specimens were subjected to drilling tests. The effect of drilling parameters on thrust force was investigated based on a design of experiments approach. A regression model was established to predict thrust force at various drilling conditions. Then, the machinability rating was defined as the ratio of the predicted thrust forces. The results showed that at lower feed rates, the thrust force is very close for both materials, such that the estimated machinability rating is 86%.