Machinability of Different Hardened Steels With Coated Ceramic Tool

This work concerns with some machinability aspects on surface roughness, tool wear and chip morphology in hard turning of AISI 4140 and AISI 4340 steels using coated ceramic tool under dry environment. The machined surface characterization, tool wear mechanism, chip morphology and economical feasibility are investigated in this study. By adopting combined techniques such as Taguchi's orthogonal array and analysis of variance, the effect of cutting parameters on surface roughness and flank wear are explored and appropriate conclusions are drawn. Additionally, the quantification of surface finish on the hardened alloy steel parts in terms of tool flank wear produced by coated ceramic insert in hard turning operations was also studied. Based on RSM, mathematical models were developed for surface roughness and flank wear with 95% confidence level. The experimental data were further analyzed to predict the optimal range of surface roughness and flank wear in finish dry hard turning of high strength low alloy steels. Finally, under optimum cutting conditions, tool life was evaluated to perform cost analysis for justifying the economic viability of coated ceramic inserts in hard turning.