Збірники наукових праць ЦНТУ
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Item Удосконалення технології розбирання металоконструкцій механізованого шахтного кріплення(ЦНТУ, 2023) Боков, В. М.; Сіса, О. Ф.; Мірзак, В. Я.; Телюта, Р. В.; Пукалов, В. В.; Bokov, V.; Sisa, О.; Mirzak, V.; Teliuta, R.; Pukalov, V.Запропоновано технологію для розбирання металоконструкцій шахтного кріплення, що дозволяє замінити фізично важку та небезпечну працю оператора на більш легкий, механізований процес з використанням потужного гідравлічного біпреса. During operation, the hinge connections of mine supports practically stop rotating. This is due to the fact that, as a result of the aggressive mine water and strong dustiness, the diametrical clearance of 1-2 mm between the axis and the bushing is tightly filled with oxides and coal dust, especially in the connections of the base. This circumstance leads to the fact that the axes (pins) in the hinges lose their mobility and require significant effort for their dismantling. To repair the mechanized mine support, it is necessary to dismantle the hinge connections, which are formed by axes and holes in levers (traverses), base ears, and overlaps. Currently, the dismantling of hinge connections of mine supports is carried out using manual impact tools. This operation is extremely labor-intensive, physically heavy, and belongs to hazardous work. The goal of the study is to improve the working conditions of the operator during the dismantling process of axes in hinge connections of mine supports by using a mechanized specialized hydraulic press. To achieve the set goal, the following tasks must be solved: to determine the maximum permissible disassembly force of the axes, taking into account the strength of the load-bearing structure elements; to develop a concept of a mechanized hydraulic press, including the composition of the installation, the general technical description, the principle of operation, the kinematic scheme, and the tool. Studies have been carried out on the deformation modeling of mine support elements under load using the SOLIDWORKS Simulation calculation module to determine the maximum permissible disassembly force of the axes. It has been shown that the disassembly load of the shaft support axis with a force of more than 1000 kN leads to the loss of the structural strength reserve, which is unacceptable. An effective technology for dismantling the axes of a mechanized mine support has been proposed. A concept of an original specialized hydraulic press "Kit-100" for dismantling axes has been developed, which allows replacing the physically heavy and dangerous work of the operator with a lighter, mechanized process.Item Дослідження процесу затвердіння та прогнозування структури литих чавунних молольних тіл(ЦНТУ, 2018) Ломакін, В. М.; Клименко, В. В.; Пукалов, В. В.; Кузик, О. В.; Дубодєлов, В. І.; Горюк, М. С.; Ломакин, В. Н.; Кузык, А. В.; Дубоделов, В. И.; Lomakin, V.; Klymenko, V.; Pukalov, V.; Kuzyk, O.; Dubodelov, V.; Goriuk, M.Розглядається використання методу скінченних елементів для чисельного розрахунку процесу затвердіння виливків молольних тіл циліндричної і сферичної форми в кокілі в залежності від хімічного складу сплаву та для прогнозування співвідношення між кількістю ледебуриту, що визначає зносостійкість молольних тіл, та кількістю аустеніто-графітної евтектики. Рассматривается использование метода конечных элементов для численного расчета процесса затвердевания отливок мелющих тел цилиндрической и сферической формы в кокиле в зависимости от химического состава сплава и для прогнозирования соотношение между количеством ледебурита, что определяет износостойкость мелющих тел, и количеством аустенито-графитный эвтектики. The aim of the study was to calculate the kinetics of crystallization and to determine the rational mode for cooling castings of a crushing cylinder and a crushing ball in metallic form to ensure that the surface wear-resistant bleached layer does not have more than a third of the size (or radius of the ball) from the surface of the body. The use of the finite element method for numerical calculation of solidification of castings of grinding bodies of cylindrical and spherical bodies in chill molds is considered depending on the chemical composition of the alloy and for predicting the ratio between the amount of ledeburite, which determines the wear resistance of grinding bodies, and the amount of austenite-graphite eutectic. The experimental chemical composition of cast iron for grinding bodies: 3-3.9% C, 2.8-4% Si, 0.6-1.2% Mn; less 0.03% P, less 0,02% S. For cylindrical and spherical bodies, the thermal conductivity functional was obtained and the kinetics of crystallization of castings was calculated. The data obtained indicate an inhomogeneity in the distribution of the linear rate of solidification along the cross-section of cast products. At the beginning of the process, the solidus front has a relatively high velocity (0.08 mm / s), which rapidly decreases with increasing thickness of the crust. Further, with the passage of time, the thickness of the two-phase zone gradually decreases and in the central part of the casting the rate of solidification is ~ 0.005 mm / sec. It is established that the microstructure of low-chromium cast iron (~ 1% Cr) is perlite-ledeburite. The carbide phase is represented by doped cementite (Fe, Cr)3С. A comparative analysis of the operational properties and the cost of their achievement showed that in today's conditions, it is a compromise to make cast grinding bodies from low-alloyed cast iron (0.8-1% Cr). The data obtained by the calculation method are in good agreement with the results of production tests of cast grinding bodies, which made it possible to optimize the technology for manufacturing such products.Item Дослідження впливу кінетики кристалізації на властивості кокільних виливків чавунних цильпебсів(КНТУ, 2016) Ломакін, В. М.; Клименко, В. В.; Пукалов, В. В.; Ломакін, А. В.; Lomakin, Viktor; Klimenko, Vasil; Pukalov, Viktor; Lomakin, AndriyРозглядається використання методу математичного моделювання для визначення часу початку і закінчення процесу кристалізації легованих чавунів у кокілі в залежності від хімічного складу сплаву та для прогнозування співвідношення між кількістю ледебуриту, що визначає зносостійкість цильпебсів (молольних циліндрів), та кількістю аустеніто-графітної евтектики. The aim of this work is studying how speed of hardening and chromium's modified additives affect to structure of cast iron's cylinder in metallic form for rising of the shock and abrasive durability. Here is examined use of mathematical modeling to identify the start time and end time of hardening alloying metal, depending on the chemical composition of the alloy, and to predict the ratio between amount of ledeburite, which determines the durability of the cylinder, and number of austenite-graphite eutectic. Comparative analysis of performance properties and value of its achievements showed that today the best compromise is to manufacture grinding bodies from cast iron . The cast iron has to be low alloyed by the chromium(0.8-1%).