OBRABOTKAMETALLOV technology Vol. 27 No. 3 2025 the cutting zone. Most of the works presented in this area are devoted to studying changes in the average temperature when one of the cutting mode parameters varies, but the effect of vibrations generated by the system itself at certain processing modes on the nature of heat dissipation in the contact zone has not been analyzed [8–12]. At the same time, studies show that cutting tool vibrations and the temperature in the cutting zone are highly correlated. For example, Songyuan Li et al. show the results of the influence of tool vibrations on temperature for different stages of tool wear [13]. Qiu Yu et al. also note the significant influence of cutting modes and tool vibrations on the thermal state in the processing zone, while noting that this relationship is characterized by nonlinear properties and depends on the operating parameters of the cutting system [14]. The temperature in the cutting zone reaches its maximum value at the end boundary of the secondary plastic deformation (SPD) zone on the tool rake face. The “tool rake face-chip” interface is a heavily loaded tribological system, in which the cutting edge of the tool heats up as a result of viscous dissipation of friction energy in the surface deformable microvolume of the chip. By applying hydrodynamic analogies to the assessment of deformation processes in the SPD layer, A.V. Chichinadze and K.G. Shuchev obtained an analytical dependence describing the temperature distribution along the rake face and allowing the maximum temperature at this edge to be determined [15]. The parameters of the volumetric heat source in the chip are determined by the specified cutting modes. At the same time, as a result of various vibration disturbances in the cutting system, one or more of the initially specified processing parameters (speed, feed, cutting depth) periodically deviate from their nominal values, changing the set of tribodeformation indicators that determine the maximum instantaneous contact temperature. As a result of the variable nature of the heat sources on the rake face, there will be periodically repeating impulsive changes in the instantaneous temperature associated with mechanical vibrations of the machine’s actuators. The specific deviation of this indicator from the nominal value will be determined by a set of values that each of the processing mode parameters takes at the moment of fluctuations. An increase in the amplitude of the variable temperature component leads to an increase in the temperature gradient in the cutting wedge as a whole and to an increase in undesirable heat flows. Temperature fluctuations in areas adjacent to the zone of primary plastic deformation change the characteristics of the material being processed and affect the cutting forces. The unstable thermal state of the cutting zone and the variable nature of the thermal load on the cutter surfaces cause intensification of oxidative and diffusion wear of the working edges of the tool [17–19]. At the same time, thermodynamic processes on the tool face largely determine the thermal state and wear processes on its flank face [20, 21]. Negative temperature effects are particularly acute during dry cutting of heat-resistant materials with low thermal conductivity [22–24]. The use of equipment with a long service life is an additional factor that increases tool vibrations and increases the temperature in the processing area. Such equipment is prone to significant kinematic disturbances originating from the feed drives and the main drive during machining. The purpose of this work is to evaluate the influence of periodic fluctuations in processing parameters, induced at different cutting speeds, on changes in the maximum temperature of the cutter’s rake face when turning heat-resistant 0.17 C-Cr-Ni-0.6 Mo-V steel on a machine with a long service life without coolant. Methods Real-life tests were carried out in production conditions (Atommash factory, Volgodonsk) on a DIP-300 universal turning machine. External longitudinal turning of workpieces with a diameter of 109 mm and a length of 400 mm made of 0.17 C-Cr-Ni-0.6 Mo-V steel was performed using cemented carbide inserts (WC 79 %; TiC 15 %, Co 6 %) with the following cutting edge geometry: back rake angle γ = 6°, clearance angle α = 6°, major cutting edge angle φ = 95°, and nose radius r = 0.5 mm. Turning was performed at a feed rate of s = 0.198 mm/rev, a cutting depth of t = 0.5 mm, and a spindle speed of n = 630–1,000 rpm (cutting speed V = 215.5–343.6m/min). Theworkpieces were centered and pre-turned. To increase the rigidity of theworkpiece subsystem, a reinforced precision rotating tailstock BISON 8814-5 NC PRECISION 20/30 was used. Tool vibrations measured in the directions of its mobility were selected as the main information channels about the dynamics of the cutting process, as they have a greater impact on fluctuations in technological
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