Notch wear prediction model in turning of Inconel 718 with ceramic tools considering the influence of work hardened layer

The alumina-based ceramic cutting tools are a kind of promising tools used in machining of heat-resistant-super-alloys, such as nickel-based super alloy, due to its high wear resistance, low thermal expansion and good oxidation resistance up to above 1000 degrees C. Sharp temperature rise mainly caused by excessive plastic deformation as well as the friction in machining of nickel-based super alloys is considered to be the key for rapid tool wear, especially the notch wear, which is the predominant type of catastrophic failure mechanism for the round type ceramic cutting tools. In this study, the wear mechanism of alumina-based ceramic cutting tools during dry turning of Inconel 718 is experimentally investigated. Based on the observation of tool wear, an attempt by employing the hardened layer beneath the workpiece surface is made to explain the occurrence of notch wear. Consequently, a predictive model of notch wear depth considering the influence of work hardened layer is developed. Series of cutting tests are used to validate the proposed notch wear model, and the result indicates that the proposed model is feasible. The contribution of this work can guide the effective control of tool wear by reducing the work hardened layer through the optimization of processing parameters. (C) 2014 Elsevier B.V. All rights reserved.