Turning machinability of alloyed ductile iron compared to forged EN 1.7131 steel

Abstract

Recently, many applications have used austempered ductile iron due to its high hardness, strength, toughness, and wear resistance. These superior properties make austempered ductile iron an alternative material to forged steels. However, machining of austempered ductile iron is challenging because of its high hardness and strength. In this study, machining operations were performed on the alloyed ductile iron workpiece to investigate the machinability of the material prior to the austempering process. This experimental study was carried out on EN 1.7131 alloy steel and alloyed ductile iron using single point carbide inserts under dry cutting conditions. A constant feed of 0.1 mm x rev(-1), constant depth of cut of 1 mm, and variable cutting speeds were selected as input parameters, whereas tool life is considered as a response parameter. The tool life tests were accomplished considering flank wear as tool life criterion according to ISO 3685. The results of this study indicated that although the machinability of ductile iron is 88% of the normalized forged EN 1.7131 steel for a 60 minutes' tool life, identical tool life was observed for both materials at 96 m x min(-1) cutting speeds.