Influence of cutting speed on pulse changes in the temperature of the front cutter surface during turning of heat-resistant steel 0.17 C-Cr-Ni-0.6 Mo-V

Introduction. This paper is devoted to the evaluation of the influence of periodic fluctuations of machining mode parameters on the change of the maximum temperature of the front surface of the cutter. Subject of research. Fluctuations of cutting mode parameters are considered as deviations of their values relative to the nominal ones, resulting in periodic changes in the cross-sectional area of the cut layer and the interaction conditions between the chip and the tool’s front surface, which affect temperature changes in the cutting zone. The purpose of this work is to evaluate the influence of periodic fluctuations of machining mode parameters at different cutting speeds on the variation of the maximum temperature of the cutting tool’s front surface during turning of heat-resistant steel 0.17 C-Cr-Ni-0.6 Mo-V on a long-life machine without cooling. Method and methodology. The finishing longitudinal turning process of heat-resistant steel 0.17 C-Cr-Ni-0.6 Mo-V on a long-life machine without cooling was investigated. During machining, tool vibrations were measured along three coordinate axes while varying the cutting speed at constant depth of cut and feed. Using digital simulation modeling based on input data obtained from in-situ experiments, the moments in the system dynamics when each cutting mode parameter reaches extreme values due to fluctuations were identified. Deviations of the maximum design temperature from the corresponding nominal value were then determined. Results and discussion. It is established that variations in machining speed change the factors destabilizing the thermal state: at low speeds, the main sources of temperature deviations in the investigated cutting system are moments when extreme values of cutting depth and speed are reached; at higher speeds, fluctuations of cutting depth and feed have the greatest effect. It is revealed that when machining parameters reach extreme values, instantaneous temperature generally increases, and cutting speeds at which such deviations are minimal are identified.