Experimental study on energy dissipation characteristics of adiabatic shear evolution in high-speed machining of U75V steel

Abstract

As one of the main characteristics in high-speed machining process, the adiabatic shear evolution induced energy dissipation influences the development of serrated chip and tool failure, which was further investigated experimentally in this work. Through the high-speed machining experiment of U75V rail steel by applying the cemented carbide insert, the development of chip morphology accompanying with the adiabatic shear evolution and tool failure with the cutting speed increasing were investigated microscopically. Based on the adiabatic shear saturation limit analysis, the energy dissipation theory was further proposed to evaluate the energy dissipation accumulation and energy dissipation rate of adiabatic shear evolution. The influences of energy dissipation characteristics related to physical and mechanical properties on the tool failure were revealed and discussed. It was concluded from the analysis of experimental results that the energy dissipation of adiabatic shear evolution from adiabatic shear banding to fracture, resulting in the thermal and mechanical coupling, mainly influenced the mechanisms of tool failure on the rake face. The occurrence of adiabatic shear fracture weakened the friction effect on the rake face. The energy dissipation theory of adiabatic shear evolution reasonably assessed the tool failure characteristics in high-speed machining process.