№ 7 (145) (2023)

The processes of spread and reduction of a heated rough piece under visco-plasticity conditions are viewed. The ratio for force stress calculating in operations, damage to the material of the rough pieces is obtained. In the branches of special en-gineering, high-strength alloys based on titanium and aluminum are used. In the branches of special engineering, high-strength alloys based on titanium and aluminum are used. These alloys have mechanical properties anisotropy. Processing of these alloys is difficult. For this reason, the pressure treatment operation is performed with heating of the deformation zone. The material in the deformation zone exhibits viscous properties. Deformation hardening and softening (stress relaxa-tion) of the material take place simultaneously. Besides, the lower the deformation rate, the greater the softening. In this regard, a constitutive equation representing these processes is found. The factor of hardening and softening creates condi-tions for reducing the power mode of pressure treatment operations and increasing the degree of primary part forming. Stress relaxation calculation with the help of analytical dependencies is necessary at the stage of expansion and pressing development. The calculated ratios are recorded as a function of the speed of these operations. In this case, the specified deformation (the change in the degree of forming) is taken into account, adjusted depending on the speed and mechanical characteristics of the bearing alloy anisotropy. The calculated ratios are obtained under conditions of a flat voltage scheme, which corresponds to expansion and pressing. Stress equilibrium equation and yield condition of anisotropic material are used. The joint solutions of this equation and yield conditions determine values of the meridional and circumferential stress-es arising in the piece part material. The values of the stresses allow calculating the forces of operations. It is shown that the speed of expansion and pressing and mechanical properties anisotropy affect the damage to the material of the «green body». Dependences for the calculation of damage are obtained on the basis of energy and deformation strength criteria. These dependencies allow predicting the quality of products. It is also shown that anisotropy affects the technological modes of expansion and pressing. As the anisotropy coefficient increases, the stresses and forces of operations decrease. Calculations of stresses, forces and material damage in the process of expansion of anisotropic titanium alloy VT14 at 875 ℃ are made.

The trends of working methods development based on the analysis of certain working methods using loose abrasive are giv-en. Along with wide technological capabilities and relatively low cost, the existing irregularities of methods are noted. The elimination of them will ensure prospective viability for the development of machining operations with the use of loose abra-sive. An approach was suggested. It consists in forming the structure of databases of working methods according to struc-tural and technological features and generating groups of methods differing in homogeneous design procedures for their development using a mathematical tools technique of cluster analysis. The article describes and provides diagrams of the developed methods of external and internal surfacing of rotation body type using a compacted layer of abrasive medium. They make it possible to get not varying qualitative characteristics, finishing through forming an area of abrasive material in the chamber with equal compaction in the places of interaction of the treated surface and abrasive grains, and to provide conditions for equalization of contact pressures on the working surface. Based on the performed research and testing of the presented methods, scientific and technical tasks have been identified, the solution of which will make it possible to imple-ment the technological support of their effective application. For the purpose of reducing the complexity of the created mod-els and the volume of experimental research, a strategy for conducting research based on the unification of individual pro-ject procedures for technological preparation of production is proposed. The obtained results allowed making theoretical substantiation of a systematic approach to the formation of an environment for automated planning of operations using loose abrasive, which consists in the creation of formalized homogeneous design procedures for grouped working methods.

Research significance is contingent on the requirement strengthening for high-speed cutting tools performance and wide-spread introduction of automatic lines and NC-machines. An increase of the tool service life is also necessary for the reduc-tion of putting expensive alloying elements to use, primarily, tungsten. The solution of these problems requires the use of technologies for hardening cutting surfaces. Combined processes of thermochemical treatment processes, uniting diffusive surface alloying with nitrogen saturation have shown their effectiveness in the surface hardening of various steels. Now the aim is to study the process of combined surface tungsten and nitrogen saturation of high-speed steel for increasing small-sized tool durability. Experimental studies were carried out on samples and small-diameter drills made of P6M5 steel. For laboratory experiments connected with combined process of thermochemical treatment an installation for nitriding in multi-component media was used. Metallization with tungsten was carried out by the slip method with parallel nitriding of the tool in a glow discharge. To determine the regime that provides the necessary temperatures for oxygen and nitrogen saturation, the temperatures of the control steel samples were measured on the surface and in the core at different durations of the cur-rent pulse in the heating phase. Metallographic analysis proved that thermochemical treatment resulted in a modified sur-face layer with a thickness of 10…15 microns, formed in P6M5 steel. The structure of the layer is an internal nitriding zone, which consists of a solid tungsten and nitrogen solution in iron and dispersed inclusions of tungsten nitrides. Dispersion and solid solution hardening provide a two-fold increase in the microhardness of the modified W-N layer compared to the alloy base. A transitional diffusion zone of nitrogenous martensite has been revealed under the hardened layer, creating a smooth microhardness gradient from the layer to the core, protecting it from embrittlement, peeling and staining. Using a metallophysical simulated test in predeveloped methodology, the calculation of the hardening index of the modified layer (yield point increase) was made. It showed that with increase in the concentration of tungsten in the layer, the proportion of the component of the dispersion hardening by W2N particles also increases. Full-scale tests in production conditions showed that the tool with a hardened layer had increased resistance. The durability of drills, determined by the number of drilled holes made before its dropping-out, increases by 2,2 times when drilling on 30XGSA steel and by more than 7,0 times when drilling a titanium alloy VT-23.

The analysis of the known friction-temperature laws is carried out in the article. A mathematical model of external friction of F.F. Ling and E. Seibel coefficient dependence on temperature, activation energies of formation and destruction of friction bonds and other factors, developed using the equations of absolute rates of chemical reactions, is analyzed. An approxima-tion of this model is implemented in temperature independence case for Bowden and Tabor shear strength. A mathematical model, describing sliding friction force-temperature relation under frictional interaction of spatially ordered rubbers hav-ing steel surface, is proposed. A distinctive feature of the proposed mathematical model is that it can simultaneously describe areas of constancy, friction force linear and nonlinear scaling under temperature changes. The testing and verification of the developed mathematical model is fulfilled through digitizing and processing experimental data, obtained by the fric-tional interaction of bars, made of spatially ordered natural rubber and spatially ordered rubber SCS-50 with a prism made of steel st.3. Analyzing the approximating dependencies, it is found, that for spatially ordered natural rubber, the maximum value of the friction force is 2,0 kgf under the temperature of approximately 37,6 ℃, and the average value of the friction coefficient is 0,987, for spatially ordered natural rubber, the maximum value of the friction force is 1.84 kgf under the tem-perature of approximately 31,4 ℃, while the average value of the coefficient of friction is 0,853. New tribotechnical charac-teristics have been introduced making possible to give a more detailed characterization of the frictional interaction in the rubber-steel system for the cases of temperature changes.

To identify products at all stages of production, a code mark is used by two-dimensional DataMatrix barcoding. Due to the fact that there are different types of surfaces, marking with the help of self-adhesive polymer film materials, where the infor-mation is recorded by a laser using the DPM (Direct Part Marking) method, is becoming increasingly popular. These films, called "laser films", are often used in manufacturing, especially in the automotive industry, as they have a number of ad-vantages compared to other information carriers. However, such films (tesa 6930, 3M 7847) are mostly imported and expen-sive, and also have an operating temperature limit of up to 250 °C, which is sometimes insufficient. The article discusses foreign and domestic films, including polymer NPM012 and organosilicon LP2. LP series are a new group of organosilox-ane–based laser films allowing the use of laser marking for parts operating up to 1000 °C. The article provides a compara-tive analysis of the labeling of polymer films and organosilicon films in accordance with international standards of auto-matic identification and data collection technologies. Laser marking is performed using a nanosecond fiber laser with a power of 30 watts and a wavelength of 1,064 microns. DataMatrix (GS1) is used as a barcode according to the Russian sys-tem of marking and keeping track of goods "Honest Mark". Marking quality assessment is carried out by scanning verifier to check the compliance validation for ISO/IEC standards. The article describes the adjustment of laser barcoding technologi-cal parameters for ensuring high-quality marking.