Cutting temperature analysis and experiment of Ti–MoS2/Zr-coated cemented carbide tool

Abstract

To improve the tribological properties of the cemented carbide, Ti–MoS2/Zr composite coatings were deposited on the substrate surface by medium-frequency magnetron sputtering coupled with multi-arc ion plating. The morphology and fundamental properties of the coatings were examined. Dry machining test on AISI 1045 hardened steel was carried out with the coated tool and uncoated tool. The variation of cutting temperature was tested by a TH5104 thermo tracer. The results showed that cutting speed had a profound effect on the cutting temperature. In low-speed cutting of less than 120 m/min, the cutting temperature was decreased by 18–22% and flank wear resistance was improved by 25–30% in comparison with that of uncoated tool, while in high-speed cutting, there was not much difference in cutting performance owing to the high temperature caused by the elevated cutting speed. Through the analysis of cutting heat distribution theory, two responsible mechanisms are found: as lubricating additive between the tool and chip sliding couple, the Ti–MoS2/Zr composite coatings contribute to the decrease of average shear stress on the rake face and the thermal barrier effect in heat conduction. These may result in the decrease of the cutting temperature of tool and chip, and hence the improvement of tool wear resistance.