PVD AlTiN coating effects on tool-chip heat partition coefficient and cutting temperature rise in orthogonal cutting Inconel 718

Abstract

Significant cutting temperature rise is induced in dry machining Inconel 718 with high cutting speed due to its low thermal conductivity and high hot hardness. PVD AlTiN coating can avoid direct contact between tool substrate and moving chip, which will affect tool-chip interface heat partition and temperature rise. However, few studies were relevant with the effect of AlTiN coating on tool-chip interface heat partition and temperature rise in dry cutting Inconel 718. In this study, the tool-chip interface temperature rises due to heat generations in primary and secondary deformation zones (PDZ and SDZ) are predicted with various heat partition coefficients, respectively. The cutting temperatures measured by two-color thermometer are utilized to determine the heat partition coefficient, and to verify the proposed interface temperature predictive model for dry orthogonal cutting Inconel 718 at cutting speed 40, 80 and 120 m/min with uncoated and PVD AlTiN coated tools. It is found that AlTiN coating decreases crater wear, and tool-chip contact length compared with that using uncoated tool. AlTiN coating decreases the maximum tool-chip interface temperature 39.00 °C and 5.47% compared with that using uncoated tool at 120 m/min. Heat partition model RG-W and RR was suitable for temperature prediction with least summary relative errors in cutting Inconel 718 with uncoated and AlTiN coated tools. The results illustrate that the PVD AlTiN coated tool could be beneficial in high-speed dry cutting Inconel 718 due to its less tool-chip interface temperature rises and tool crater wear.