Evaluation of Chip-tool Interface Temperature: Effect of Tool Coating and Cutting Parameters during Turning Hardened AISI 4340 Steel

In the present context of sustainable manufacturing, investigation of cutting temperature during machining is extremely valuable to address metal cutting issues such as dimensional accuracy, surface finish and tool life. In this study, average chip-tool interface temperature was investigated considering the effect of cutting parameters and the type of coating (coated tools), namely, PVD- applied single-layer TiAlN and CVD-applied multi-layer TiCN/Al2O3/TiN during turning of hardened steel. Mathematical model which can predict the average chip-tool interface temperature was developed based on experimental observations which were obtained in the wide range of cutting conditions. A calibration set-up based on tool-work thermocouple principle was developed to correlate the emf (electro motive force) and the interface temperature. R-squared value for the developed model found 0.9693, indicate that the developed model is reliable and could be used effectively for predicting the interface temperature within the domain of the cutting parameters for the given tool and work material pair. Experimental observations indicate that the interface temperature is higher for CVD-coated multi-layer coated tool in comparison to single-layer TiAlN, which get affected mostly by cutting speed followed by feed. However, depth of cut has negligible influence on interface temperature when using both the coated carbide tools.