Influences of TiAlN Coating on Cutting Temperature during Orthogonal Machining H13 Hardened Steel

TiAlN has been widely used in cutting tool coating due to its excellent mechanical and thermal performances. However, the research on the TiAlN coating effect on cutting temperature is not comprehensive enough. In this paper, the friction tests at elevated temperature and hard machining H13 hardened steel tests are conducted by using TiAlN coated tools and uncoated tools, respectively. The results of using TiAlN coated tools are compared with those from using uncoated tools. It is found that the coefficient of friction (COF) between TiAlN coated tool and H13 hardened steel is reduced to 0.63 at 800 degrees C. The COF value is 0.75 for uncoated tool. Under the same cutting conditions, the TiAlN coating shortens tool-chip contact length. The tangential cutting forces and cutting zone temperatures are decreased with smaller COF and shorter tool-chip contact length. Due to the lower thermal conductivities of TiAlN coating and the Al2O3 oxide layer formatted at tool rake face, the cutting heat conducted into cutting tool substrate was reduced. The cutting temperatures in TiAlN coated tool substrate are decreased by at least 10.68% in this study. The TiAlN coating reduces the cutting temperature by decreasing the cutting heat generation and conduction.