Modeling of temperature distribution in turning of Ti-6Al-4V with liquid nitrogen cooling

A predictive thermal analytical model based on the improved Oxley's theory and the image heat source method for orthogonal cutting was proposed to obtain the exact temperature distributions in the chip, tool, and workpiece during cryogenic machining. The influences of some important factors, including the shear deformation at primary zone, the friction at tool-chip interface, and the heat losses at both rake and flank faces of the tool caused by liquid nitrogen jetting, were all considered in the thermal model. The heat loss of rake face was divided into contact and non-contact zones to calculate the cooling effects at different positions. Heat partition ratios were utilized to modify the non-uniform distribution at tool-chip interface for all the heat sources and losses, respectively. The cutting parameters were optimized to avoid the low precision and efficiency of iterative algorithm. Cryogenic turning experiments were performed to verify the analytical model of temperature distribution. The results showed that the average errors of the predicted temperatures were lower than 3.30%.