Investigating the machinability evaluation of Hadfield steel in the hard turning with Al2O3/TiC mixed ceramic tool based on the response surface methodology

In this study a series of tests were conducted in order to investigate the machinability evaluation of Hadfield steel in the hard turning. The austenitic Hadfield steels, containing about 1.0–1.2% C and 11–14% Mn in mass, have excellent wear-resistance property and are extensively used in various engineering applications. The cutting tool used was an uncoated Al2O3/TiC mixed ceramics which is approximately composed of 70% of Al2O3 and 30% of TiC. In this paper, an attempt had been made to model the machinability evaluation through the response surface methodology (RSM) in machining Hadfield steel. The combined effects of four machining parameters, including cutting speed, feed rate, depth of cut and tool corner radius, on the basis of two performance characteristics—flank wear (VBmax) and surface roughness (Ra), were investigated and the centered central composite design (CCD) and the analysis of variance (ANOVA) were employed. The quadratic model of RSM associated with the sequential approximation optimization (SAO) method was used to find optimum values of machining parameters. Results show that the flank wear is influenced principally by the cutting speed and the interaction effect of feed rate with nose radius of tool, and the cutting speed and the tool corner radius have statistic significance on the surface roughness. The optimal settings of machining parameters obtained in this study represent the reduction of the 9.25% flank wear and the 8.74% surface roughness, which were compared with the results of initial machining parameters for machining Hadfield steel in the hard turning process.