Effects of cutting parameters on tool wear in milling inconel 625 superalloys with a SiAlON ceramic and the prediction of tool life

Inconel 625 superalloys are widely preferred in various industries because of their superior mechanical properties at high temperatures. The superior properties they exhibit make the machinability of Inconel 625 alloys difficult. This situation can cause rapid wear of the cutting tools, making the cutting tool unusable in very short periods of time and causing deterioration of the workpiece surface quality. Therefore, improving the machining performance of Inconel 625 alloys, optimizing the machining parameters and using the optimum cutting tool material and geometry are important. In this study, SiAlON ceramic cutting tools, which have been widely used in recent years, were preferred. SiAlON tools supplied in raw rod form were subjected to various processes and finalized into final products. The effects of three different cutting speeds (vc), feed rates (f) and axial depth of cut (ap) on tool life (T), wear patterns and mechanisms were investigated with 9 tests designed according to the Taguchi L9 orthogonal array. The results revealed that the f values, the effects of which were analysed, had the most significant effect on T. By performing regression analysis with T values, the coefficients used in the extended Taylor T equation were determined, and T predictions were obtained. The regression model was found to be consistent with the experimental results, with an effect of 99.34 %, and the model was significant according to analysis of variance. The predominant wear patterns of the cutting tools were flaking at a low vc, nose collapse at a high vc and an adhered workpiece under all conditions. The wear mechanism was found to be predominantly adhesion and fracture. The presence of Ni, Cr, Mo, Nb and Fe on the cutting tool surface was determined, and the effect of the concentrations was observed to increase/decrease significantly depending on the parameter values examined.