Special structural low-alloy high-carbon steel 65G, belongs to the spring-spring family. One of the most popular Russian grades of spring steel, which is suitable for creating responsible industrial parts. A small amount of alloying additives provides the relative cheapness of the alloy, which makes it extremely popular. In the manufacture of special products, there are a lot of technological difficulties associated with ensuring the form, optimality of production material and time costs. The use of promising methods of electrochemical processing of parts is relevant.

The study of high-speed anodic dissolution of steel 65Г was carried out by the potentiostatic method on a ПИ-50-1.1 device(potentiostat) at a potential rate of 5∙10–2 mV/s using electrolytes based on NaNO3 with the addition of glycerol, triethanolamine, ethyl alcohol, sodium benzoate, hydrogen peroxide. To determine the limiting step of high-speed dissolution, the effect of the electrode rotation speed was studied, which ranged from 200 to 1000 rpm. At the electrode rotation speed of 1000 rpm, an active anode dissolution region was detected. When adding additives with increase of concentration of triethanolamine, sodium benzoate, ethyl alcohol, increase of current density in active area is established, and in anode-anionic area potential of anodic-anionic activation beginning is shifted to area of positive potentials and decrease of anode current density is observed.

Dependence of current output values on electrolyte nature under identical polarization conditions is revealed. It was found that the highest current yield was observed with the introduction of 10 % ethyl alcohol and 0.5 % hydrogen peroxide. When polarizing electrodes under galvanostatic conditions, the microstructure of the treated surface was studied. Based on the results of the studies, electrolytes with increased resistance to pitting and the lowest surface roughness after polarization for steel 65G were recommended.

Keywords: high-speed anodic dissolution, polarization, potentiostat, galvanostatic studies, electrolyte, steel, current output, limiting stage, anodic-anionic region, potential, current density, surface roughness.

Albina R. Khamzina (Ufa, Russian Federation) – Candidate of Technical Sciences, Associate Professor of Mechanical Engineering Department of UGATU (12, K. Marx str., Ufa, 450008, Russian Federation, e-mail: FATSTM@yandex.ru).

Adel S. Kvyatkovskaya (Ufa, Russian Federation) – Candidate of Technical Sciences, Associate Professor, Acting Head of the Department of Green Chemistry and Resource-Saving Technology, USATU (12, K. Marx str., Ufa, 450008, Russian Federation, e-mail: kvyatkovskay@mail.ru).

Yulia B. Saburova (Ufa, Russian Federation) – Candidate of Technical Sciences, Associate Professor of the Department of Green Chemistry and Resource-saving Technology, USATU (12, K. Marx str., Ufa, 450008, Russian Federation, e-mail: kutnyakova@mail.ru).

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The possibility of complex pyrometallurgical processing of Hg–Se–Al compositions of variable composition at reduced pressure with the production of monoelement products is investigated. Object of research: Hg–Se–Al compositions of the composition, mol%: 33-5 Hg, Se; 34-90 Al, formed during the processing of copper electrolyte sludge in the process of obtaining commercial selenium concentrate. The aim of the work: determination of the evaporation rate of elements from Hg–SeAl compositions of various compositions depending on temperature and residual pressure, as well as identification of the limiting stage of the process. Methods and approaches: the molecular interaction volume model (MIVM) was used to calculate the activity coefficients of the alloy components. Novelty: the obtained process parameters characterize experimentally determined values of the evaporation rate of components of polymetallic systems and the apparent activation energy. Main results: the rate of sublimation of components from Hg–Se–Al systems at a temperature of 823–1073 K and a pressure of 1.33–133 Pa corresponds to the kinetic model described by the first-order equation; the coefficients of total mass transfer of mercury, selenium, aluminum (kMe) during evaporation from Hg–Se–Al composition of the composition 0,33–0,33–0,34 make up, m.sec-1: (1.62–2.83).10‒6, (0.67–1.29).10‒6, (1.66–5.12).10‒8, at T = 823‒1073 K, p = 13.3 Pa, respectively; activation energy of evaporation of components from Hg–Se–Al melt, kJ/mol: EMe = 16.3–33.7, which is lower than for individual metals: EMe = 58.5–284.1; the quantitative transfer of Hg and Se in the gas phase is not a limiting stage, since the sublimation of the Hg–Se–Al components of the composition is determined by mass transfer in the melt, which determines the overall speed of the process. Practical relevance: the revealed parameters of the kinetics of evaporation of components from the composition of Hg–Se–Al compositions, which are the initial information for the design of technological equipment for industrial production of vacuum distillation, as well as for determining the optimal ranges of temperature and pressure of the process in order to obtain Se-containing products of a given composition as a result of sublimation.

Keywords: mercury, selenium, aluminum, composition, separation, kinetics, vacuum distillation, activation energy, mass transfer coefficient, activity coefficient.

Alexey A. Korolev (Verkhnyaya Pyshma, Russian Federation) – Ph.D. in Technical Sciences, Сhief engineer of JSC “Uralelectromed” (1, Uspenskij prospect, Verkhnyaya Pyshma, 624091, Russian Federation, e-mail: A.Korolev@elem.ru).

Vladimir A. Shunin (Verkhnyaya Pyshma, Russian Federation) – Deputy Head of the Research Center of JSC "Uralelectromed", (1, Uspenskij prospect, Verkhnyaya Pyshma, 624091, Russian Federation, e-mail: V.Shunin@elem.ru).

Konstantin L. Timofeev (Verkhnyaya Pyshma, Russian Federation) – Doctor of Technical Sciences, Head of the Technical Department of JSC “Uralelectromed” (1, Uspenskij prospect, Verkhnyaya Pyshma, 624091, Russian Federation,e-mail: K.Timofeev@elem.ru).

Gennady I. Maltsev (Verkhnyaya Pyshma, Russian Federation) – Doctor of Technical Sciences, Senior Researcher, Chief Specialist of the Research Center of JSC “Uralelectromed” (1, Uspenskij prospect, Verkhnyaya Pyshma, 624091, Russian Federation, e-mail: mgi@elem.ru).

Roman S. Voinkov (Verkhnyaya Pyshma, Russian Federation) – Ph.D. in Technical Sciences, Нead of the Research center of JSC “Uralelectromed” (1, Uspenskij prospect, Verkhnyaya Pyshma, 624091, Russian Federation,
e-mail: A.Krauhin@elem.ru).

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The paper describes the concept of creating and controlling the anisotropy of materials using magnetic fields as a promising method for controlling the structure and final properties of composites. Samples of carbon-ceramic composite material were obtained by slip casting under an ultra-low constant magnetic field (5–10 µT) with further spark plasma sintering in vacuum at a temperature of 1200 °С with a holding time of 5 minutes and a pressing pressure of 2.6/6.2 kN. Highly dispersed titanium dioxide powder (TU 31-10-020-90, LLC "Composite") was used as a feedstock, polyvinyl alcohol (PVA) and multi-walled carbon nanotubes of the trademark "Taunit-M" ("NanoTechCenter", Tambov) were used as a binder. To visualize the passage of magnetic field lines through the casting channel with different arrangement of magnets, samples were additionally obtained with the addition of micron iron powder as a ferromagnet. It is shown that it is possible to use various combinations in the arrangement of magnets relative to the casting channel, in order to obtain a different distribution of the filler in the volume of matrices for various applications in instrumentation and mechanical engineering. The structure of the samples was studied by scanning electron microscopy, X-ray microanalysis, X-ray computed tomography. The results of scanning electron microscopy showed that under the influence of a weak magnetic field, carbon nanotubes are assembled into agglomerates, which are stretched from one pole to another throughout the entire sample. Computed tomography studies did not allow differentiation of carbon nanotubes and pores in the ceramic matrix due to a weakly pronounced phase contrast.

Keywords: anisotropy, multi-walled carbon nanotubes, carbon-ceramic slip, constant magnetic field, spark plasma sintering, scanning electron microscopy, X-ray computed tomography, phase contrast, phase distribution maps.

Svetlana E. Porozova (Perm, Russian Federation) – Doctor of Technical Sciences, Associate Professor, Department of Mechanics of Composite Materials and Constructions, Perm National Research Polytechnic Universty
(29, Komsomolsky ave., Perm, 614990, Russian Federation, e-mail: keramik@pm.pstu.ac.ru).

Tatyana Yu. Pozdeeva (Perm, Russian Federation) – Postgraduate Student, junior researcher, Department of Mechanics of Composite Materials and Constructions, Perm National Research Polytechnic University (29, Komsomolsky ave., Perm, 614990, Russian Federation, e-mail: pozdeevatu@gmail.com).

Alyona S. Lebedeva (Perm, Russian Federation) – Engineer, Department of Mineralogy and Petrography, Perm State National Research University (15, st. Bukirev, Perm, 614990, Russian Federation, e-mail: alenal5@rambler.ru).

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Advanced technological processes for the construction of oil and gas wells require the use of equipment with high strength and reliability characteristics. During the construction of wells, the drilling tools experiences significant loads and the influence of an aggressive environment associated with abrasive and corrosive wear of the outer and inner surfaces.

Increasing the resource and creating new equipment is possible only with the involvement of materials science.

The drill string kit includes drill pipes of various types and KBDC equipment (kit bottom of the drilling columns). Drill pipes are made of pearlite grade steel. The KBDC includes components made of austenitic steel with the required anticorrosive and non-ferromagnetic properties.

When performing work on the repair and restoration of the technical parameters of drill pipes and components of the KBDC by the surfacing method, various types of molten metal deposition on the surface of the equipment are used.

This work is directed at determining the role of surfacing in the formation of the structure of the main zones of products and the mechanical properties of pearlite and austenitic class of steels.

The structure of the surfacing, the HAZ (heat affected zone) surfacing, the friction welding zone, the overlap of the HAZ surfacing and the HAZ weld were investigated. A weak influence on the mechanical properties of the overlapped zones is displayed. The mechanical properties before and after the creation of the compounds differed insignificantly. Grain sizes and interplate distances were measured. The samples were cut directly from completed products, the strengthening mechanisms of both classes of steels were determined, the advantages of pearlite and austenitic steels over ferrite-perlite steels currently used were shown. Frequently a mixed type of structure is formed in the weld, but sorbite was considered the best until recently. With the occurrence of the austenitic class of steels, it will significantly improve the performance of technological equipment. Strength, reliability and corrosion resistance are expected to increase. It should be noted, however, the increased cost of high-alloy austenitic steel due to the increased content of two or three alloying elements, among which there are usually chromium.

Keywords: Oil and gas wells, drilling columns, aggressive environment, strength, ductility, viscosity, hydrogen sulfide, carbon dioxide, corrosion resistance, structural strength, surfacing, structure, perlite, sorbitol, ferrite, austenite, martensite.

Sergey К. Laptev (Perm, Russian Federation) – Ph.D. Student, Department of Metal Science, Thermal and Laser Processing of Metals, Perm National Research Polytechnic University (29, Komsomolsky ave., Perm, 614066, Russian Federation, e-mail: sklaptev@bk.ru).

Alexander А. Shatsov (Perm, Russian Federation) – Doctor of Technical Sciences, Professor, Department of Metal Science, Thermal and Laser Processing of
Metals, Perm National Research Polytechnic University
(29, Komsomolsky ave., Perm, 614066, Russian Federation, e-mail: shatsov@pstu.ru).

Sergey K. Grebenkov (Perm, Russian Federation) – Ph.D. in Technical Sciences, Leading engineer, Department of Metal Science, Thermal and Laser Processing of
Metals, Perm National Research Polytechnic University
(29, Komsomolsky ave., Perm, 614066, Russian Federation, e-mail: drive@rtural.ru).

Dmitry S. Laptev (Belfast, Great Britain) – Student, IYO BEng Aerospace Engineering, Queens University Belfast (6, Rowan Gardens, Belfast, Great Britain, e-mail: dmitriilaptevs@gmail.com).

1. Babenko A.A., Zhuchkov V.I., Sel'menskikh N.I., Upolovnikova A.G. Struktura i svoistva nizkouglerodistoi trubnoi stali 17G1S–U, mikrolegirovannoi borom [Structure and properties of boron microalloyed low-carbon pipe steel 17Mn1Si-H]. Izvestiia vysshikh uchebnykh zavedenii. Chernaia metallurgiia, 2018, vol. 61, no. 10, pp. 774–779.

2. Uglov V.A., Zaitsev A.I., Rodionova I.G. Os-novnye napravleniia razvitiia metallurgicheskoi tekhnologii dlia obespecheniia sovremennykh trebovanii po urovniu i stabil'nosti tekhnologicheskikh i sluzhebnykh svoistv stali [The main directions of metallurgical technology development to ensure modern requirements for the level and stability of technological and service properties of steel]. Chernaia metallurgiia. Biulleten' nauchno-tekhnicheskoi i ekonomicheskoi informatsii, 2012, no. 3 (1347), pp. 85–94.

3.   Denisova T.V., Ioffe A.V., Tetiueva T.V. Oso-bennosti formirovaniia struktury v nizkolegirovannoi stali 08KhMFBChA pri zakalke i otpuske [Peculiarities of structure formation in low-alloy steel 08KhMFBCHA during quenching and tempering]. Metallovedenie i termicheskaia obrabotka metallov, 2012, no. 10, pp. 34–38.

4.   Gol'dshtein M.I., Grachev S.V., Veksler Iu.G. Spetsial'nye stali steels]. Moscow: MISIS, 1999, p. 408.

5.   Special Badicioiu M., Ripeanu R. G., Dinita A., Minescu M., Laudacescu E. Tribological characterization of the drill pipe tool joints reconditioned by using welding technologies. IOP Conf. Series: Materials Science and Engineering, 2018, vol. 295, p. 012010.

6.   Chudyk I., Poberezhny L., Hrysanchuk A., Poberezhna L. Corrosion of drill pipes in high mineralized pro-duced waters. 6th Int. Conf. “Fracture Mechanics of Materials and Structural Integrity” Procedia Structural Integrity, 2019, vol. 16, pp. 260–264.

7.   Han L., Hu F., Wang H., Feng Y., Li H. A new method to determine the required impact toughness for petroleum drill pipe used in critical sour environment. Procedia Engineering, 2011, vol. 16, pp. 667–672.

8.   Ianturin A.Sh., Sultanov B.Z. Spiral'naia de-formatsiia kolonny trub v naklonnoi skvazhine [Spiral deformation of a pipe string in a deviated well]. Neft' i gaz, 1977, no. 5, pp. 15–20.

9.   Yan H., Xuehu Z., Zhenquan B., Chengxian Y. Failure Analysis on Fracture of a S135 Drill Pipe. Procedia Materials Science, 2014, vol. 3, pp. 447–453.

10.    Fangpo L. Investigation on impact absorbed energy index of drill pipe. Engineering Failure Analysis, 2020, vol. 118, p. 104823.

11.    Sedmak A., Grbović A., Kirin S., Šarkočević Ž., Zaidi R. Material Effects on Risk Assessment of Residual Life of Oil Drilling Rig Pipe. Procedia Structural Integrity, 2020, vol. 28, pp. 1315–1320.

12.    Emrea H.E., Kaçarb R. Effect of Post Weld Heat Treatment Process on Microstructure and Mechanical Properties of Friction Welded Dissimilar Drill Pipe. Materials Research, 2015, vol. 18 (3), pp. 503–508.

13.    Priymak E., Atamashkin A., Stepanchukova A. Effect of Post-Weld Heat Treatment on The Mechanical Properties and Mechanism of Fracture of Joint Welds Made by Thompson Friction Welding. Materials Today: Proceedings, 2019, vol. 11, pp. 295–299.

14.    Urtsev V.N. Fazovye i strukturnye prevrashcheniia v staliakh [Phase and structural transformations in steels]. Sbornik nauchnyh trudov. Ed. V.N. Urtseva. Magnitogorsk, 2008, iss. 5, pp. 62–75.

15.    Kristian D., Roitburd A.L. Teoriia prevrashchenii v metallakh i splavakh [Theory of Transformations in Metals and Alloys]. Termodinamika i obshchaia kineticheskaia teoriia. Moscow: Mir, 1978, pach. 1, p. 807.

16.    Saroian A.E. Truby neftianogo sortamenta: spravochnik [Petroleum pipes: handbook]. Moscow: Nedra, 1987, p. 504.

17.    Saroian A.E. Buril'nye kolonny v glubokom burenii [Drill strings in deep drilling]. Moscow: Nedra, 1979, p. 231.

18.    Gorynin V.I., Kondrat'ev S.Iu., Olenin M.I., Rogozhkin V.V. Kontseptsiia karbidnogo konstruirovaniia sta-lei povyshennoi khladostoikosti [The concept of carbide design of cold-resistant steels]. Metallovedenie i termicheskaia obrabotka metallov, 2014, no. 10, pp. 32–37.

19.    Rekin S.A. Sovershenstvovanie tekhnologii ekspluatatsii buril'noi kolonny (na primere AO «Purneftegaz­geologiia») [Improvement of drill string operation technology (by the example of Purneftegazgeologiya JSC)]. PhD thesises. Samara, 1997, p. 137.

20.    Erlikh G.M. Ekspluatatsiia buril'nykh trub [Drill pipe operation]. Moscow: Nedra, 1969, p. 312.

21.    Dong L., Zhu X., Yang D. Study on mechanical behaviors of double shoulder drill pipe joint thread . Petroleum, 2019, vol. 5, pp. 102–112.

22.    Rekin S.A., Ianturin A.Sh. Ustoichivost', uprugaia deformatsiia, iznos i ekspluatatsiia buril'nykh i obsadnykh kolonn [Stability, elastic deformation, wear and performance of drill strings and casing]. Mekhanika sistemy «kolonna skvazhina – plast». Saint-Petersburg: Nedra, 2005, p. 439.

23.    Fain G.M., Neimark A.S. Proektirovanie i ekspluatatsiia buril'nykh kolonn dlia glubokikh skvazhin [Design and operation of drill strings for deep wells]. Moscow: Nedra, 1985, p. 237.

24.    Lachinian L.A. Rabota buril'noi kolonny [Drill string operation]. Moscow: Nedra, 1992, p. 212.

25.    Odintsov L.G. Uprochnenie i otdelka detalei poverkhnostnym plasticheskim deformirovaniem [Strengthening and finishing of parts by surface plastic deformation]. Moscow: Mashinostroenie, 1987, p. 328.

26.    Kompozitsionnye materialy s metallicheskoi matritsei [Composite materials with metal matrix]. Ed. K. Kreider, K.I. Portnogo. Moscow: Mashinostroenie, 1978, p. 502.

The article considers the main factors leading to a decrease in the accuracy of parts. An increase in deviations of their shape, caused by stress relaxation, inevitably leads to a decrease in reliability and a decrease in the service life of machines, and a decrease in their operational properties.

The task of stabilizing geometrical parameters is especially acute for the production of precision rolling bearings of accuracy classes 6 and higher, which are widely used in various machines and assemblies. Even a slight change in dimensions during a certain period of time leads to a sharp loss in the accuracy of these bearings.

An analysis of the stress state of parts such as a bearing ring shows that if their transverse and longitudinal sections are symmetrical about the main central axes of these sections, then there is no deviation in the geometric shape of the rings over time. In real conditions of manufacturing rings, their transverse and longitudinal sections are not symmetrical with respect to the main central axes of these sections. Since the relaxation rate depends on the level of stresses, relaxation occurs primarily in those parts of the ring where the maximum stresses act.

The object of research in this work are the rings of the bearing unit of the belt tensioner of the car (tension rollers) of the following types 2108-1006120-01, 2112-1006120-01. The control of the studied parameters of the parts was carried out using the following equipment, namely: a MAR 3 diffractometer, a FARO ARG EDGE coordinate measuring machine.

Theoretical and experimental dependences of bearing rings deformations and residual stresses depending on the time of ultrasonic stabilization of internal stresses and the required time of ultrasonic treatment on the required values of deformations and residual stresses of bearing rings are presented.

Keywords: bearing, residual stresses, relaxation, ovality, parameters, control, standard deviation, stray field, mathematical expectation, dispersion, ultrasound.

Marina G. Babenko (Saratov, Russian Federation) – Ph.D. in Technical Sciences, Ass. Professor, Department of Technology and Control Systems of Yuri Gagarin State technical university of Saratov (77, Polytehnicheskaya st., Saratov, 410054, Russian Federation, e-mail: babenkomg@mail.ru).

Sergey V. Slesarev (Saratov, Russian Federation) – Ph.D. in Technical Sciences, Ass. Professor, Department of pedagogy, education technology and professional communication of the Saratov State Medical University named after
V.I. Razumovsky (112, Bolshaya Kazachia st., Saratov, 410012, Russian Federation, e-mail: ser-slesarev@yandex.ru).

Currently, in production there is a problem of fulfilling casting errors during the subsequent machining of products. When assembling the measuring measurement of the flow section, it depends on the complexity of manufacturing the casting profiles of the blades and the perfect setting of the parameters of each individual nozzle blade. The article presents the results of the development and application of special software for taking into account deviations in the casting profiles of the blade feather and calculating the area of the flow section of the correction path to the CNC rack of a multi-axis grinding machine model MFP-050.65.65 from Magerle AG.

To accomplish this task, a software package (software) for preparing data for grinding blades has been developed, which includes SSS (specialized software) for automated calculation of displacement values and rotation angles of nozzle and rotor blades, analysis and editing of the flow area of castings and blades. The results of preliminary testing show an improvement in the quality of both the surface of the flow path and the flow section. Testing of the SPO and refinement based on the results of testing continues, experiments are being carried out on the example of the 2nd nozzle blade for the PD-14 engine. Application of the technology of deep grinding of base surfaces of nozzle blades of turbines on the five-axis machining center Magerle MFP-050.65.65 will allow processing with a minimum number of installations, better quality and greater productivity. Thanks to the use of special software, it will be possible to determine the values of displacements and angles of rotation, providing compensation for casting errors and taking into account the flow area in the blades. The result of the joint use of new equipment and SPO will be a decrease in the spread of values of the area of the passage section in the nozzle apparatus. As a result, the efficiency of the engine will increase and the likelihood of unwanted vibrations will decrease.

Keywords: section through passage, turbine shovels, deep grinding, profile surfaces, grinding circles, quality of a surface, a turn corner, quantity of passes, errors of moulding of shovels.

Vladimir F. Makarov (Perm, Russian Federation) – Doctor of Technical Sciences, Professor Department of «Innovation technologies in mechanical engineering», Perm National Research Polytechnic University (29, Komsomolsky ave., Perm, 614990, Russian Federation, e-mail: makarovv@pstu.ru).

Aleksandr O. Norin (Perm, Russian Federation) – Postgraduate Student of the Department of «Innovation technologies in mechanical engineering», Perm National Research Polytechnic University (29, Komsomolsky ave., Perm, 614990, Russian Federation).

Mikhail V. Pesin (Perm, Russian Federation) – Dr. Sci. Tech., the professor, The dean of mechanical technological faculty, Faculty of Mechanics and Technology, Perm National Research Polytechnic University (29, Komsomolsky ave., Perm, 614990, Russian Federation, e-mail: m.pesin@mail.ru).

1.   Kozlov D.A. PD-14 sozdaetsia prakticheski vse-mi aviadvigatelestroiteliami Rossii [PD-14 is created by almost all aircraft engine builders in Russia]. URL: http://www.aviaport.ru/news/2012/04/16/ 233024.html (data avalable 15.10.2014).

2.   Inozemtsev A.A., Sandratskii V.L. Gazoturbinnye dvigateli [Gas turbine engines]. Perm', 2006, 1195 p.

3.   Nikhamkin M.A., Zal'tsman M.M. Konstruktsiia osnovnykh uzlov dvigatelia PS-90A [Construction of the PS-90A engine main units]. 2nd. Perm': Permskii gosudarst­vennyi tekhnicheskii universitet, 2002, 108 p.

4.   Makarov V.F. Sovremennye metody vysoko­effektivnoi abrazivnoi obrabotki trudnoobrabatyvaemykh materialov [Modern Methods of Highly Effective Abrasive Processing of Hard-to-Machine Materials]. Perm': PNIPU, 2013, 359 p.

5.   Poletaev V.A., Volkov D.I. Glubinnoe shlifovanie lopatok turbin: biblioteka tekhnologa [Turbine Blade Deep Grinding: Technologist's Library]. Moscow: Mashino­stroenie, 2009, 272 p.

6.   Makarov V.F., Turanskii R.A., Grigor'eva A.V. Povyshenie tochnosti prokhodnogo secheniia soplovykh lopatok turbin [Improving the accuracy of the nozzle section passage of turbine blades]. Materialy nauchno-prakticheskoi konferntsii. Briansk, 2015, pp. 291–293.

7.   Makarov V.F., Norin A.O. Avtomatizirovannyi raschet velichiny smeshchenii soplovykh lopatok turbiny s obespecheniem zadannogo prokhodnogo secheniia soplovogo apparata [Automated calculation of turbine nozzle blade displacements to provide a given nozzle passage section]. Aerokosmicheskaia tekhnika, vysokie tekhnologii i innovatsii-2014: materialy XV Vseros. NTK 4–6 iiunia 2015. Perm': PNIPU, 2015, pp. 25–29.

8.   Makarov V.F., Norin A.O., Turanskii R.A. Razrabotka metoda korrektiruiushchego upravleniia pro-tsessom glubinnogo shlifovaniia bazovykh poverkhnostei soplovykh lopatok na mnogoosevom stanke s ChPU [Development of a method for corrective control of the process of deep grinding of base surfaces of nozzle blades on a СMM multi-axis machine]. Sovremennye vysokoeffektivnye tekhnologii i oborudovanie v mashinostroenii (MTET-2016): materialy nauchno-tekhn. konferentsii, 6–8 oktiabria 2016. Saint-Petersburg: Gosudarstvennyi politehnicheskii universitet Petra Velikogo, 2016, pp. 23–27.

9.   Makarov V.F., Nikitin S.P., Norin A.O. Po-vyshenie kachestva i proizvoditel'nosti pri profil'nom glubinnom shlifovanii turbinnykh lopatok [Improvement of quality and productivity in profile depth grinding of turbine blades]. Naukoemkie tekhnologii v mashinostroenii, 2016, no. 5(59), pp. 29–31.

10. Makarov V.F., Norin A.O., Nikitin S.P., Turanskii R.A. Osobennosti tekhnologicheskogo obespecheniia prokhod­nogo secheniia lopatok turbin pri glubinnom mnogoosevom shlifovanii na stanke s ChPU [Peculiarities of technological support of the passage section of turbine blades during deep multiaxis grinding on a CNC machine]. Mashinostroenie i tekhnosfera XXI veka: sbornik trudov XXIII materialov nauchno-tekhnicheskaia konferentsiia, 12–18 sentiabria 2016, Sevastopol'. Donetsk, 2016, vol. 2, pp. 127–128.

11. Makarov V.F., Norin A.O. Avtomatizirovannyi raschet velichin smeshchenii soplovykh lopatok turbiny s obespecheniem zadannogo prokhodnogo secheniia soplovogo apparata [Automated calculation of turbine nozzle blade displacements to provide a given nozzle passage section]. Naukoemkie tekhnologii na sovremennom etape razvitiia mashinostroeniia: sbornik trudov XXIII materialov nauchno-tekhnicheskoi konferentsiia, 19–21 maia. Moscow: MADI, 2016.

12. GP «Ivchenko-Progress»: Obrabotka lopatok na profileshlifoval'nom stanke firmy Mägerle [Machining blades on a Mägerle profile grinding machine]. Promyshlennost' v fokuse, 2013, no. 1.

13. Informatsiia o sisteme ChPU Siemens Sinumerik: portal [Information about the Siemens Sinumerik control system]. URL: http://iadt.siemens.ru/products/motors_ drives/sinumerik/CNC_controls/840d_sl/. (data avalable 20.03.2015).

14. OAO «Aviadvigatel'»: portal [Aviadvigatel
JSC: portal]. URL: http://www.avid.ru/ (available at:
20.03.2015).

15. Na razrabotku spetsializirovannogo pro-grammnogo obespecheniia dlia opredeleniia velichin sme-shchenii i uglov povorota, dlia kompensatsii pogreshnosti lit'ia lopatok i ucheta prokhodnogo secheniia: tekhnicheskoe zadanie [For the development of specialized software to determine the values of displacements and angles of rotation, to compensate for the error of casting blades and accounting for the passage section: terms of reference]. OAO «Aviadvigatel'», 2014.

16. Makarov V.F. Sovremennye metody vysokoeffektivnoi abrazivnoi obrabotki zharoprochnykh stalei i splavov: uchebnoe posobie [Modern Methods of Highly Effective Abrasive Processing of Heat-Resistant Steels and Alloys]. Saint-Petersburg: Lan', 2013, 320 p.

17. Poletaev V.A., Volkov D.I. Glubinnoe shlifovanie lopatok turbin: biblioteka tekhnologa [Turbine Blade Deep Grinding: Technologist's Library]. Moscow: Mashinostro­enie, 2009, 272 p.

18. Novoselov Iu.K. Dinamika formoobrazova-niia poverkhnostei pri abrazivnoi obrabotke [Dynamics of Surface Shaping in Abrasive Machining]. Saratov: Izdatelstvo Saratovskogo universiteta, 1972, 232 p.

19. Nikitin S.P. Modelirovanie protsessa rezaniia pri shlifovanii s uchetom vzaimodeistviia uprugoi i teplovoi sistem [Simulation of the cutting process in grinding, taking into account the interaction of elastic and thermal systems]. Vestnik UGATU, 2009, vol. 12, no. 4 (33), pp. 61–65.

20. Starkov V.K. Shlifovanie vysokoporistymi krugami [Grinding with highly porous grinding wheels]. Moscow: Mashinostroenie, 2007, 688 p.

21. Makarov V.F., Nikitin S.P. Povyshenie kachestva i proizvoditel'nosti pri profil'nom glubinnom shlifovanii turbinnykh lopatok [Improvement of quality and productivity in profile depth grinding of turbine blades]. Naukoemkie tekhnologii mashinostroeniia, 2016, no. 5 (59), pp. 17–24.

22. Makarov V.F., Nikitin S.P. Povyshenie ef-fektivnosti profil'nogo glubinnogo shlifovaniia lopatok turbin na mnogokoordinatnykh stankakh s ChPU [Improving the efficiency of profile depth grinding of turbine blades on CNC multiaxis machines]. Naukoemkie tekhnologii mashinostroeniia, 2018, no. 4 (82), pp. 21–28.

23. Nikitin S.P. Rezul'tativnost' protsessov dolzhna rabotat' na rezul'tat [Process efficiency must work for results]. Vestnik PNIPU. Mashinostroenie, materialovedenie, 2013, vol. 15, no. 1, pp. 109–114.

24. Noichl H. CBN Grinding of Nickel Alloys in the Aerospace Industry. Intertech 2000. Vancouver, 2000. July 17–21.

Currently, composite materials are used as a replacement for traditional materials in order to improve the characteristics and efficiency of the operational properties of structures for various purposes. In the case of friction nodes, it is necessary to take into account factors characteristic of the composite materials used in them, such as the influence of structural components or the heterogeneity of the medium.

The article considers a model of contact interaction of unidirectional fibrous composites with a tetragonal arrangement of fibers to determine the coefficient of friction of the material.

To solve the contact problem, it is proposed to use the method of local approximation, which is based on the effect of short-range order in the interaction of inhomogeneities and is based on the principle of locality. The ANSYS application package was used for the numerical implementation of the problem. In two-dimensional modeling of the stress state in the steel-composite contact zone, a finite element grid with four nodes (Plane 182) was used and the condition of ideal contact at the interface was applied. To account for the effect of the wear value on the coefficient of friction in a steel-composite pair, four configurations of a tetragonal cell in the contact zone were simulated.

As a result of the study, the change in the coefficient of friction for the steel-composite pair was determined depending on the amount of wear and the distribution fields of normal and contact stresses in the components of the composite material structure were obtained. The coefficient of friction of the composite in the reinforcement plane significantly depends on the degree of wear of the material, is determined by the structure of the inhomogeneous material in the contact zone and the corresponding distribution of structural stress fields

The described research methodology in the article allows us to consider tribological characteristics from the perspective of mechanics of composite materials.

Keywords: coefficient of friction, fibrous composite materials, polymer composite materials, numerical modeling, contact stresses, local approximation method, unidirectional composite materials, tetragonal structure, dry friction, tribological characteristics.

Denis D. Palkin (Perm, Russian Federation) – Engineer, Postgraduate at the Department of Mechanics of Composite Materials and Structures, Perm National Research Polytechnic University (29, Komsomolsky ave., Perm, 614990, Russian Federation, e-mail: 13denis01@mail.ru).

Andrey A. Chekalkin (Perm, Russian Federation) – Doctor of Physico-mathematical Sciences, Professor, Professor of the Department of Mechanics of Composite Materials and Structures, Perm National Research Polytechnic University (29, Komsomolsky ave., Perm, 614990, Russian Federation, e-mail: a.a.chekalkin@yandex.ru).

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2.   Makarova E.Iu., Sokolkin Iu.V., Chekalkin A.A. Strukturno-fenomenologicheskie modeli prognozirova-
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3.   Vashukov Iu.A. Issledovanie napriazhenno-deformirovannogo sostoianiia soedineniia izdelii iz kompozitsionnykh materialov [The study of the stress-strain state of the joints of products made of composite materials]. Izvestiia Samarskogo nauchnogo tsentra RAN, 2009, vol. 11, no. 3(2), pp. 414–419.

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25. Kragel'skii I.V. Koeffitsienty treniia: spravochnoe posobie [Coefficients of Friction: Reference Manual]. Moscow: MAShGIZ, 1962, 220 p.

26. Buznik V.M., Lur'e S.A., Volkov-Bogorodskii D.B., Kniazeva A.G., Soliaev Iu.O., Popova E.I.    Ob uchete masshtabnykh effektov pri modelirovanii mekhanicheskikh i tribologicheskikh svoistv dvukhfaznykh mikro- i nanomodifitsirovannykh polimernykh pokrytii [On accounting for scale effects when modeling mechanical and tribological properties of two-phase micro- and nanomodified polymer coatings]. Vestnik Permskogo natsional'nogo issledovatel'skogo politekhnicheskogo universiteta. Mekhanika, 2015, no. 4, pp. 36–54.

Stress-strain state analysis of the antifriction layer with a spherical lubricant hole was carried out as part of the work. A comparison of the deformation behavior of an interlayer made of 2 polymeric materials is presented: the modified PTFE and the antifriction composite material based on PTFE with spherical bronze inclusions and molybdenum disulfide (MAK). To describe the behavior of antifriction materials, the deformation theory of elastoplasticity was chosen, physical and mechanical properties were obtained during field experiments at low deformation rates: under the condition of uniaxial stressed state, uniaxial deformed state, determination of hardness according to Brinel. The range of working loads arising in the spans of bridge structures that reach 90 MPa is considered. All types of the state of the steel-polymer contact pair are considered: sticking, sliding, near contact. As part of the work, an analysis was made of the convergence of the numerical solution of the problem on the degree sampling of the system. A numerical experiments series on the deformation of the periodicity cell with a thickness of 4, 6 and 8 mm, cut out from the antifriction material volume, was carried out as part of the study. Dependencies from the load are tuned: stress intensity, plastic strain intensity, contact status, contact pressure and contact tangential stress. In the MAK layer, with an increase in load, there is no hole for the lubricant, due to the large deformation of the material on the mating surface, complete “sticking” prevails, the material remains in a state of slippage in the area where there is no hole, as it tends to fill micro voids. It has been established that the interlayer from modified PTFE is less susceptible to deformation for all variants of the sliding layer thickness.

Keywords: polymer, composite material, contact, friction, deformation behavior, lubricatio, sliding layer, material properties, large deformations, thickness.

Anatoliy A. Adamov (Perm, Russian Federation) – Doctor of Physical and Mathematical Sciences, Senior Researcher, Leading Researcher of the Laboratory of Nonlinear Mechanics of a Deformable Solid Body ICMM (1, st. Academica Koroleva, Perm, 614013, Russian Federation,
e-mail: adamov.aa@ya.ru).

Anna A. Kamenskih (Perm, Russian Federation) – Ph. D. In Technical Sciences, Ass. Professor, Department of «Computational mathematics mechanics and biomechanics» (13, st. Professora Pozdeeva, Perm, 614013, Russian Federation, e-mail: anna_kamenskih@mail.ru).

Yuriy O Nosov (Perm, Russian Federation) – Ph.D. student of «Computational mathematics mechanics and biomechanics» (13, st. Professora Pozdeeva, Perm, 614013, Russian Federation, e-mail: ura.4132@yandex.ru).

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7.   Bulatov M.I., Azanova I.S., Kosolapov A.F., Smirnova A.N., Saranova I.D. Issledovanie vliianiia otritsatel'nykh temperatur na opticheskie poteri volokonnogo svetovoda v zashchitno-uprochniaiushchem pokrytii na osnove poliamidokisloty [Study of the Effects of Negative Temperatures on Optical Loss of Fiber Optic Fiber in a Polyamide Acid-based Protective-Strengthening Coating]. Kratkie soobshcheniia po fizike FIAN, 2019, vol. 46, no. 9, pp. 9–13.

8.   Adamov A.A., Kamenskikh A.A., Pankova A.P. Influence analysis of the antifriction layer materials and thickness on the contact interaction of spherical bearings elements. Lubricants, 2022, vol. 10, no. 2, Art. 30.

9.   Sulaiman M.H., Nordin N.H., Sukindar N.A., Dahnel A.N., Kamaruddin S. Friction and wear behaviours of hardcoated uncoated bearing steels under nano-additive oil lubrication. Lecture Notes in Mechanical Engineering, 2022, pp. 65–68.

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29. Adamov A.A., Kamenskih A.A., Pankova A.P. Numerical analysis of the spherical bearing geometric con-figuration with antifriction layer made of different materials.  PNRPU Mechanics Bulletin, 2020, no. 4, pp. 15–26.

Aluminum alloys of the Al–Mg–Li alloying system are widely used in aircraft construction due to their properties. The main difficulty in welding aluminum alloys is related to the formation of pores. This paper presents metallographic studies of pores in welded joints of aluminum alloy obtained by argon-arc welding with AMg-6 filler wire. The analysis was carried out under different illumination in order to correctly identify the pores, their location and shape. If in the light field it is quite difficult to distinguish pores from inclusions, then with gradual extinguishing: from the light field, to the polarized light and dark field, it is possible to observe their clear glow in the aureole. According to the results of the research, it was found that pores in welded joints are present in different areas of the weld. Their primary location was revealed along the alloying line and along the boundaries of the weld layers. The pores have different shapes and sizes. Their distribution varies from single pores to clusters up to 4–5 per 1 cm. Since hydrogen is considered to be the main cause of pore formation in welded joints of aluminum alloys, the reasons of its impact on pore formation were analyzed. On the basis of literature data and the results obtained, it was found that during cooling of the weld pool, hydrogen, redistributing into molecules, forms gas bubbles. The formed bubbles, due to changes in solubility, float up. This process occurs as long as the viscosity of the surrounding metal allows. In addition, it has been revealed that welded joints have a rather extended fusion zone during argon-arc welding, and the magnesium content will reduce hydrogen diffusion and metal viscosity, which makes it difficult for gas bubbles to pop up after metal crystallization, leading to porosity formation.

Keywords: porosity, weld, hydrogen, aluminum alloy, alloying, pores, metallography, welding, oxide film, alloying zone.

Tatyana V. Olshanskaya (Perm, Russian Federation) – Doctor of Technical Sciences, Professor, Department of Welding Production, Metrology and Technology of Materials, Perm National Research Polytechnic University
(29, Komsomolsky ave., Perm, 614990, Russian Federation, e-mail: tvo66@rambler.ru).

Elena M. Fedoseeva (Perm, Russian Federation) – Ph.D. in Technical Sciences, Associate Professor, Department of Welding Production, Metrology and Technology of Materials, Perm National Research Polytechnic University (29, Komsomolsky ave., Perm, 614990, Russian Federation, е-mail: emfedoseeva@pstu.ru).

1. Fridliander I.N. Vospominaniia o sozdanii aviakosmicheskoi i atomnoi tekhniki iz aliuminievykh splavov [Memories of Aerospace and Nuclear Engineering in Aluminum Alloys]. Otdelenie khimii i nauk o materialakh RAN. 2nd. Moscow: Nauka, 2006, 287 p.

2. Krivov G.A., Riabov V.R., Ishchenko A.Ia., Mel'nikov R.V., Chaiun A.G. Svarka v samoletostroenii [Welding in aircraft construction]. Ed. B.E. Patona. Moscow: Izdatelstvo MIIVTs, 1998, 690 p.

3. Alieva S.G., Al'tman M.B., Ambartsumian S.M. Promyshlennye aliuminievye splavy [Industrial aluminum alloys:]. 2nd. Moscow: Metallurgiia, 1984, 528 p.

4. Lukin V.I., Grushko O.E. Osobennosti vliianiia metallurgicheskikh faktorov proizvodstva splava 1420 na kachestvo svarnykh soedinenii [Peculiarities of the influence of metallurgical factors of alloy 1420 production on the quality of welded joints]. Svarochnoe proizvodstvo, 1998,
no. 1, pp. 8–9.

5. Ren L., Gu H., Wang W., Wang Sh., Li Ch., Wang Zh., Zhai Yu., Ma P. Efect of Mg Content on Microstructure and Properties of Al–Mg Alloy Produced by the Wire Arc Additive Manufacturing Method. Materials, 2019, vol. 12,
p. 4160. DOI: 10.3390/ma12244160

6. Luo Ch., Li, H., Zhang, Yu., Li, J., Wen, Yu., Yang, L. Microstructure and Mechanical Properties of Tungsten Inert GasWeld Joints of Sprayed and Cast Aluminium–Lithium Alloy. Materials, 2020, vol. 13, pp. 3787.
DOI: 10.3390/ma13173787

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pp. 2375–2380.

11. Mel'nikov A.A., Bunova G.Z. Tekhnologiia ter-moobrabotki aliuminievykh polufabrikatov [Technology of semi-finished aluminum heat treatment]. Samara: Samarskii gosudarstvennyi aerokosmicheskii universitet imeni akademika S.P. Koroleva, 2006, 128 p.

12. Fedoseeva E.M., Ol'shanskaia T.V., Prokhorov P.V. Metallograficheskie issledovaniia svarnykh shvov aliuminievogo splava sistemy Al–Mg–Li, podvergnutogo termovakuumnoi obrabotke [Metallographic examination of welds of Al-Mg-Li system aluminium alloy subjected to thermo-vacuum treatment]. Vestnik Permskogo natsional'nogo issledovatel'skogo politekhnicheskogo universiteta. Mashinostroenie, materialovedenie, 2020, vol. 22, no. 1, pp. 40–53. DOI: 10.15593/2224-9877/2020.1.05

13. Grinin V.V., Lopatkin A.I., Ovchinnikov V.V. et al. Osobennosti svarki tonkolistovykh konstruktsii iz splava 1420 [Peculiarities of welding thin-sheet structures made of alloy 1420]. Svarochnoe proizvodstvo, 1985, no. 8, pp. 13–15.

14. Lukin V.I., Iakushin B.F., Nastich S.Iu. Issledovanie svarivaemosti sverkhlegkikh Al–Mg–Li splavov [Study of weldability of ultralight Al-Mg-Li alloys]. Svarochnoe proizvodstvo, 1996, no. 12, pp. 15–20.

15. Fedoseeva E.M., Ol'shanskaia T.V. Termokine-ticheskii raschet fazovogo sostava svarnykh shvov aliuminievogo splava 1420 sistemy Al–Mg–Li. Chast' 1. Termokineticheskii raschet fazovogo sostava splava 1420 [Thermokinetic calculation of the phase composition of welds of aluminum alloy 1420 of Al-Mg-Li system. Part 1. Thermokinetic calculation of the phase composition of alloy 1420]. Vestnik Permskogo natsional'nogo issledovatel'skogo politekhnicheskogo universiteta. Mashinostroenie, materialovedenie, 2020, vol. 22, no. 4, pp. 48–55. DOI: 10.15593/2224-9877/2020.4.07

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19. Sterenbogen, Iu.A. Primenenie matematiche-skikh metodov pri reshenii novykh zadach v oblasti sva-rochnoi nauki i tekhniki [Application of Mathematical Methods in Solving New Problems in Welding Science and Technology]. AN USSR. Ordena Lenina i ordena Trudovogo Krasnogo Znameni institut elektrosvarki im. E. O. Patona. Kiev, 1968, 11 p.

20. Fedoseeva E.M., Ol'shanskaia T.V. Termokineti­cheskii raschet fazovogo sostava svarnykh shvov aliuminievogo splava 1420 sistemy Al–Mg–Li. Chast' 2. Termokineticheskii raschet fazovogo sostava svarnogo shva, vypolnennogo provolokoi Sv-AMg-6 [Thermokinetic calculation of the phase composition of welds of aluminum alloy 1420 of Al-Mg-Li system. Part 2. Thermokinetic calculation of the phase composition of welds made by Sv-Amg-6 wire]. Vestnik Permskogo natsional'nogo issledovatel'skogo politekhnicheskogo universiteta. Mashinostroenie, materialovedenie, 2021, vol. 23, no. 2, pp. 62–69. DOI: 10.15593/2224-9877/2021.2.08

21. Fedoseeva E.M., Ol'shanskaia T.V. Issledovanie vliianiia termovakuumnoi obrabotki i elektronno-luchevoi svarki na formirovanie svarnogo soedineniia i fazovogo sostava aliuminievogo splava 1420 [Study of the effect of vacuum heat treatment and electron-beam welding on the formation of the welded joint and the phase composition of aluminum alloy 1420]. 4aia mezhdunarodnaia konferentsiia «Elektronno-luchevaia svarka i smezhnye tekhnologii»: materialy konferentsii. FGBOU VO «NIU «MEI» 16–19 noiabria 2021. Moscow: Izdatelstvo MEI, 2021, pp. 372–287.

Today the field of education, like many other areas of life, is undergoing changes. One of these changes is the introduction of individualisation of the learning process. This article examines the problem of students' attitudes towards the implementation of individual educational trajectories in universities. The relevance of the problem under study is due to the widespread introduction of individual educational path in higher education institutions. The idea of individualization of education is stated in a number of documents, including the Federal Law "On Education in the Russian Federation".

The aim of the work is to study problematic issues in the formation of individual path of undergraduate students and to identify their opportunity to participate in designing the content of their educational programme The legal status of students and the possibility of providing individual education. The paper provides a literature review of articles related to the changes in the educational process in higher education institutions. An analysis of credit-module systems prevalent in various countries around the world is given.

An empirical research method was used in the study - a survey in which one hundred and fifty undergraduate students took part. The main questions in the survey were related to the students' desire to build their educational process with the help of tutors, the choice of elective courses, as well as the need and assessment of tutors' work in their university.

Results of the research: the analysis of possible problems of application of individual educational trajectories for undergraduate courses in higher education institutions was carried out, also the readiness of students to transfer to individual educational path under the condition of professional supervision of tutors was determined.

Keywords: Universities, individual educational trajectories, education, students, tutor, European education, MOOCs, credits, elective courses, stages of education, changes in education, educational process.

Maria S. Ostapenko (Tyumen, Russian Federation) – Ph.D. in Technical Sciences, Ass. Professor, Department of Machines and tools Federal State Budget Educational Institution of Higher Education « Industrial University of Tyumen» (38 Volodarskogo st., Tyumen, 625000, Russian Federation, e-mail: ms_ostapenko@mail.ru).

Vladlena Yu. Nazarova (Tyumen, Russian Federation) – Master's student in the Technological machinery and equipment field Federal State Budget Educational Institution of Higher Education « Industrial University of Tyumen»
(38 Volodarskogo st., Tyumen, 625000, Russian Federation, e-mail: nazarova_vy@mail.ru).

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