Composite layer-based analytical models for tool–chip interface temperatures in machining medium carbon steels with multi-layer coated cutting tools

This investigation is devoted to the thermal problems in dry orthogonal turning of a C45 medium carbon steel with natural contact tools treated with multi-layer coatings with an intermediate Al2O3 layer. New hybrid analytical models for estimating heat partition to the chip and the tool–chip interface temperatures were proposed. Furthermore, the physics-based modelling concept, which applies composite layer approach was developed to estimate the average and maximum steady-state tool–chip interface temperatures in orthogonal turning. The model predictions were compared to appropriate experimental process data using natural tool-work thermocouples and other simulated and measured literature data. It was verified that the models proposed yield accurate average temperatures and estimate their maximum values for uncoated and two multi-layer coated tools for cutting speeds ranging from 90 to 240 m/min.