Problems of Tribology = Проблеми трибології - 2019 рік

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https://elar.khmnu.edu.ua/handle/123456789/7827

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Перегляд Problems of Tribology = Проблеми трибології - 2019 рік за Автор "Stechyshyn, M.S."

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  • Ескіз
    Документ
    Cavitation and erosion wear resistance of carbon structural steels
    (Хмельницький національний університет, 2019) Skyba, M.Ye.; Oleksandrenko, V.P.; Stechyshyn, M.S.; Martynyuk, A.V.; Скиба, М.Є.; Олександренко, В.П.; Стечишин, М.С.; Мартинюк, А.В.
    In the paper, based on the analysis of literary sources and own researches of authors, the results of cavitation and erosion wear resistance of structural steels are systematized depending on their thermal processing (structure) and type of environment. The structural structure of steels is based on the analysis of wear resistance during cavitation and erosion fracture of surfaces, and the mechanisms of cavitation fracture of dodectoid, zavectotoid and perlite steels are considered. Destruction of dodectoid steels begins with ferrite, and then extends to perlite grains. The wear resistance of the pearlite grains of the plate-shaped form is higher than that of perlite of the granular form. Cavitation wear resistance of zeutectoid steels is determined mainly by the properties of perlite. The mechanical properties of which depend on the dispersion and shape of the particles of cementite. In perlite steels, reducing the size of its grain increases their erosion resistance, especially in the presence of cementite in the structure of the grid, and not ferrite grids. Using different types of thermal and thermocyclic heat treatment, it is possible to form appropriate structures and, accordingly, increase the cavitation and erosion wear resistance.
  • Ескіз
    Документ
    Fuel of the keeping needs of the energy discharge during nitrogen on the tribological chara
    (Khmelnytskyi National University, 2019) Stechyshyna, N.M.; Stechyshyn, M.S.; Martyniuk, A.V.
    The effect of power discharge category W in BATR on tribological characteristics of nitrous steel 45 is investigated in the work. The highest wear resistance of steel 45 corresponds to mode 7, which provides optimum physico-chemical characteristics of the nitrided layer. The ratio of the intensities of the passage of the main BATR subprocesses determines the structure and phase composition of the nitrided layers. Depending on the current combination of parameters of the mode of formation of the nitrided layer, the intensity of the flow of the above subprocesses (nitride formation, sputtering and diffusion saturation of the surface with nitrogen), and therefore the intensity of the formation of certain phases may be different, and sometimes reverse. For example, as the energy of the incident stream W increases, the pre-formed nitride layer is sprayed, which stimulates the process of nitrogen diffusion into the metal base and the formation of ε and γ - phases. When the flow energy is insufficient to atomize the nitride layer, it acts as a kind of barrier that impedes or completely stops the process of nitrogen diffusion. It is established that the decrease in the specific discharge power leads to a decrease in the thickness of the nitride and diffusion zones and, as a consequence, the tribological characteristics deteriorate. It is revealed that at the maximum values of energy parameters, a nitrous containing layer is formed ε, γ і α - phase. The decrease in voltage and current density causes the particle to increase γ - pfase (Fe4N) and according to the reduction of the share ε - phase (Fe2N). At minimum values of energy parameters of formation of nitrides on the surface is absent and the nitrided layer consists only of α - phase.