KSHP. OMD №12-2024
A. I. Kanareykin (Russian State University for Geological Prospecting (MGRI), Moscow)
Calculation of optimal cutting conditions with tools made of hard alloys
The article is devoted to the issues of the methodology for determining the operating parameters of metal cutting. It examines the thermally stressed state in the chip formation zone during metal cutting, and also establishes dependencies for assigning the main parameters of the cutting process and developing a computational method for determining the machinability of metal materials. Using formulas obtained on the basis of a simplified model of the chip formation process, it is possible to successfully predict optimal cutting conditions.
Keywords: processing parameters; cutting tool; cutting process; cutting speed; stresses; safety margin.
A. I. Kanareykin (Russian State University for Geological Prospecting (MGRI), Moscow)
Determination of the temperature field of a cylinder with variable volumetric heat dissipation
The work is devoted to the issues of thermal conductivity. It considers the problem of determining the temperature field of a cylinder under a boundary condition of the first kind. In this case, the coordinate dependence of heat release is taken into account. The paper also analyzes the behavior of the temperature field of the cylinder along its cross section. The solution is given in the Cartesian coordinate system. It is shown that the temperature difference between the center of the cylinder and its surface is parabolic. The result obtained can be useful for determining the thermally stressed state of machine parts.
Keywords: temperature field; cylinder; heat transfer; thermal conductivity; volumetric heat dissipation; boundary conditions of the first kind; Laplace operator.
N. M. Bobrovskij, R. U. Kamenov, P. A. Melnikov (Togliatti State University, Togliatti)
Development of a mathematical model of surface formation during surface plastic deformation processing
The article presents the results of numerical modeling of the surface smoothing process, including such key aspects as plastic deformation of the material, formation of grooves, lateral extrusion of the material, and elastic recovery after passing the tool. A special feature of the model is that it takes into account the complex interaction of the tool with the material, which allows for a more accurate description of changes in the surface texture during the smoothing process. The model is based on the physical principles of contact interaction, and the process parameters are defined in accordance with international standards (ISO 4287) and modern research data. The initial surface is generated taking into account the typical roughness for fine turning, which ensures a realistic initial state. The modeling takes into account the width of the lateral extrusion zone of the material, gradual elastic recovery of the deformed material, and the change in the amplitude of microroughness after each pass of the tool. The results show that the smoothing process can significantly reduce the surface roughness. The proposed model allows not only to evaluate changes in roughness, but also to study the influence of various process parameters on the final surface quality, which is especially important for practical application in industry.
Keywords: surface plastic deformation; mathematical model; hard-to-machine materials; burnishing; processing technologies.
A. Yu. Izobello (Physical-technical Institute of the National Academy of Sciences of Belarus, Minsk, Republic of Belarus)
Study of the mechanisms of evolution of the structural state and properties of steel of the Cr-Ni-Mo-V system under severe plastic deformation
The study of the microstructure and mechanical properties of 45Kh2NMFBA steel samples obtained by a new method of severe plastic deformation in combination with high-temperature thermomechanical treatment was carried out. The conditions of the process and obtaining the necessary mechanical characteristics of the steel were determined. The results of computer modeling of repeated equal-channel bending during rolling are presented.
Keywords: severe plastic deformation; rolling; thermomechanical treatment; steel; microstructure; mechanical properties; residual stresses.
V. A. POPOV (National University of Science and Technology «MISIS», Moscow)
Metal-matrix composite materials with nanodiamond reinforcing particles
The composite materials are made of chromium or copper alloy with zinc (34 % zinc) by mechanical alloying. The reinforcing particles are nanodiamonds, the amount of which is 5–20 %. The nanodiamonds were mixed with metals for 3–4 hours. Mechanical alloying was carried out for 5–10 minutes and then cooling is carried out for 5 minutes. Studies of the obtained materials showed that at least 70% of the nanodiamonds are completely crushed. The nanodiamonds remaine stable during heating to a temperature of 450 °C. With further increase in temperature, the diamond structure begins to change into carbon. In a composite with a chromium matrix and non-agglomerated nanodiamonds, the interaction between chromium and carbon begins at 565 °C with the formation of Cr2C. With an increase in temperature, Cr23C6, Cr7C3, Cr3C2 appear. In composites with chromium and copper-zinc matrices, at least 70 % of non-agglomerated nanodiamonds were obtained
Keywords: metal matrix composite materials; nanodiamond particles; chromium matrix; copper-zinc matrix.
N. M. Bobrovskij, I. S. Yasnikov, R. U. Kamenov (Togliatti State University, Togliatti)
Review of modern research on surface plastic deformation of hard-to-machine materials
The article considers methods of surface plastic deformation (SPD) of hard-to-machine materials. The article presents the results of studies demonstrating the influence of SPD different parameters on the microhardness, residual stresses and fatigue strength of materials. The data on the key parameters and results of SPD are summarized, which emphasizes its advantages over traditional methods of surface treatment, such as thermal and shot blasting. It is shown that optimization of SPD parameters can significantly improve the quality of the surface layer and extend the service life of components. The relevance of further research for the development of universal recommendations and the implementation of innovative approaches, such as vibration-enhanced SPD and numerical modeling, to improve the efficiency of processing hard-to-machine materials is substantiated.
Keywords: surface plastic deformation; hard-to-machine materials; residual stresses; burnishing; processing technologies.
V. V. Yashin, I. A. Latushkin (JSC SAMARA METALLURGICAL PLANT, Samara); E. V. Aryshensky, S. V. Konovalov, D. N. Klepov, (SibSIU, Novokuznetsk); R. V. Shevelev (Samara University, Samara)
Development of a methodology for accounting for the effect of coolant thickness on the friction coefficient during hot rolling of aluminum alloy strips
A method is proposed for determining the friction coefficient depending on the lubricating film thickness during rolling of aluminum alloys in continuous mills. Using the reverse recalculation method of the Karman–Tselikov equation, the friction coefficients during rolling in a continuous group of stands were calculated and compared with the lubricating film thickness determined using the adjusted Wilson–Valovita equation. The described model is used to predict friction conditions throughout the rolling cycle in a hot rolling mill when operating on an «oil in water» emulsion.
Keywords: hot rolling; aluminum alloys; friction coefficient; lubricating film thickness.