Experimental Investigations and Optimization of the Machinability Aspects of AISI 4340 Alloy Steel Using Uncoated Carbide and Coated Cermet Inserts in Dry Hard Turning

Comparisons were made between the performances of uncoated carbide and coated cermet inserts for various machinability aspects during machining of hardened alloy steel (AISI 4340, 48 HRC) under dry cutting environment. Spindle speed, feed and depth of cut were considered as major governing parameters. Workpiece surface temperature, machining forces and tool flank wear were taken as measures to compare the performance estimation of different cutting inserts in this work. All the three input variables were observed to have influence over workpiece surface temperature, feed and radial force in case of both carbide and cermet. The machining operations can be performed at a higher spindle speed without compromising results when cermet inserts are used. Cermets exceeded the performance of carbides for flank wear, cutting force and workpiece surface temperature, though carbides outperformed cermets regarding feed and radial force. The depth of cut was found to be the most significant when feed and cutting forces were concerned, while it was true for radial force using carbides. Speed affected workpiece surface temperature and flank wear for carbides the most, meanwhile this was same when considering radial force with cermets. Feed was the most important parameter while the flank wear of cermets were taken in to account