The friction mechanics model within chip-tool-workpiece dual interfaces for cutting nickel-based superalloy at the cooling and lubrication conditions of the three forms oil-on-water mist in wide temperature range

Abstract

Nickel based superalloy has been extensively applied in the critical mechanical bearing components, such as aeroengine owing to its excellent performance at high temperature, but its machinability has always been dissatisfied. In order to improve processing efficiency, reduce cost, and decrease environmental pollution, in this paper, the friction mechanics model within chip-tool-workpiece dual interfaces was established in turning of S-type difficult-to-machine nickel based superalloy Inconel 718 utilizing the PVD TiAlN coated carbide tool under the cooling and lubrication conditions of three forms oil-on-water mist in wide temperature range (-30 ℃ ~ 150 ℃)(high temperature oil-on-water mist (150 ℃), normal temperature oil-on-water mist (20 ℃), and low temperature oil-on-water mist (-30 ℃)). Meanwhile the influence law and mechanism of the cutting speed, depth of cut, and feed on the three-way cutting forces, friction coefficient between chip-tool-workpiece dual interfaces, and normal stress and tangential stress in chip-tool interface have been studied. The results showed that the lowest and highest friction coefficient within chip-tool interface was obtained at the conditions of the high temperature oil-on-water mist (HTOoW) and the normal temperature oil-on-water mist (NTOoW), respectively.The most notable influence of the low temperature oil-on-water mist (LTOoW) on the strain hardening, strain rate hardening, and thermal softening of the materials occurred.