OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 26 No. 4 2024 regions (average size of the perfection regions D), approximately by 20 %, which in the experiment corresponds to larger values of the half-widths of the X-ray refl ections (Fig. 4) and slight increase in the cell parameters Conclusion The changes in the structure, microstructure and hardness of the material of the compression piston rings of the HIMSEN 4H21/32 auxiliary marine engine, which occur as a result of operation, are experimentally established in this work, using X-ray diff raction and metallographic analysis methods. Adiff erence of half-widths of X-ray diff raction refl ections of iron in the material of the upper compression ring in comparison with the lower one is established, which testifi es to the reduction of the average size of coherent scattering regions due to diff erent conditions of operation of the rings. At the same time, a diff erence in the dislocation density of 1.6 times is observed, it is 9.3 1011 cm−2 for the lower compression ring and 14.8 1011 cm−2 for the upper compression ring. A diff erence in the values of microstrains for the two rings is also established (for the lower compression ring, microdeformations are approximately 1.3 times higher). It should also be noted that the crystal lattice parameters of iron for the upper ring are increased compared to the lower ring. Thus, the results of metallographic and X-ray analyses indicate a higher degree of defectiveness of the upper compression ring as compared to the lower ring due to a greater refi nement of microcrystallites and the appearance of stronger stresses due to dislocations and inelastic deformations during ring operation. The results obtained show that to increase the durability and stability of the rings, it is necessary to harden the rings material itself, as well as the surfaces of these rings. It is expedient to evaluate changes in the manifestations of the stress state of cast iron under the infl uence of various factors. This will allow selecting the optimal technology of compression rings manufacturing to ensure the reliability of its operation. Quality control of rings using various methods also makes it possible to predict the conditions under which compression rings may be damaged during operation. References 1. Putintsev S.V. Mekhanicheskie poteri v porshnevykh dvigatelyakh: spetsial’nye glavy konstruirovaniya, rascheta, ispytanii [Mechanical losses in piston engines: special chapters of design, calculation, testing]. Moscow, Bauman MSTU Publ., 2011. 288 p. 2. Guzhvenko I.N., Chanchikov V.A., Pryamukhina N.V., Strinzha E.A. Issledovanie eff ektivnosti ispol’zovaniya sloistogo modifi katora treniya v tsilindroporshnevoi gruppe sudovogo dizel’nogo dvigatelya [Researching of the effi ciency of the use of a layer frequency modifi cator in the cylinder-piston group of the ship diesel engine]. Morskie intellektual’nye tekhnologii = Marine Intellectual Technologies, 2018, vol. 3-1 (41), pp. 135–142. 3. Taylor D.A. Introduction to marine engineering. London, Boston, Butterworths, 1990 (Russ. ed.: Teilor D.A. Osnovy sudovoi tekhniki. Moscow, Transport Publ., 1987. 320 p.). 4. Voznitskii I.V., PundaA.S. Sudovye dvigateli vnutrennego sgoraniya. T. 1 [Marine internal combustion engines. Vol. 1]. Moscow, Morkniga Publ., 2010. 260 p. 5. Skoblo T.S., Sidashenko A.I., Klochko O.Yu., Saychuk A.V., Rybalko I.N. Otsenka lokal’noi strukturnoi neodnorodnosti v otlivkakh iz serogo chuguna [Evaluation of local structural inhomogeneity in castings from the grey cast-iron]. Agrotekhnika i energoobespechenie, 2017, vol. 4 (17), pp. 141–150. (In Russian). 6. Martyushev N.V., Pashkov E.N. Bronze sealing rings defects and ways of its elimination. Applied Mechanics and Materials, 2013, vol. 379, pp. 82–86. DOI: 10.4028/www.scientifi c.net/AMM.379.82. 7. Anisovich A.G., Andrushevich A.A. Mikrostruktury chernykh i tsvetnykh metallov [Microstructures of ferrous and non-ferrous metals]. Minsk, Belaruskaya navuka Publ., 2015. 131 p. ISBN 978-985-08-1883-6. 8. Skoblo T.S., Klochko O.Yu., Belkin E.L., SidashenkoA.I.,Avetisyan V.K. Strukturoobrazovanie vysokokhromistykh chugunov v intervale temperatur magnitnogo prevrashcheniya karbidnykh faz [Structure formation of highchromium cast irons in the temperature range of magnetic transformation of carbide phases]. Pis’ma o materialakh = Letters on materials, 2020, vol. 10 (2), pp. 129–134. DOI: 10.22226/2410-3535-2020-2-129-134.
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