Effects of minimum quantity lubrication strategy with internal cooling tool on machining performance in turning of nickel-based superalloy GH4169

During the cutting process of superalloy, intense heat will be generated. Traditional external flood cooling methods require a large amount of coolant, bringing high cutting costs, serious environmental pollution, and other adverse effects. In this paper, a method combining minimum quantity lubrication (MQL) and internal cooling is proposed to accurately spray the cutting fluid into the cutting area in turning nickel-based superalloy. The heat source model for micro-lubrication cutting was established, and the heat transfer coefficient and friction coefficient under different cooling methods were calculated. Hereafter, a two-dimensional cutting finite element model was established to analyze the nickel-based superalloy turning process under different cooling conditions. Subsequently, the turning experiment of nickel-based superalloy GH4169 was carried out on the self-built turning experimental platform. The influence of different cooling methods and cutting parameters on cutting force, cutting temperature, surface roughness, chip morphology, and surface morphology of the processed workpiece was systematically studied. Furthermore, the surface roughness prediction model is obtained through the experiment results. The simulation and experiment results show that under the same cutting parameters, the cutting temperature of MQL with internal cooling is significantly lower than that of dry cutting, indicating a better cooling effect of MQL with internal cooling. Moreover, the surface morphology quality of micro-lubrication cutting is prominent compared with dry cutting. Also, the larger the cutting fluid flow, the better the surface quality. Therefore, the proposed MQL turning with internal cooling method is an environmental-friendly technology with promising application prospects.