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Автоматизація порційної розливки розплаву чавуну в кокіль при виробництві виливків деталей машин гірничорудної промисловості
(ЦНТУ, 2020) Ломакін, В. М.; Пукалов, В. В.; Дубодєлов, В. І.; Горюк, М. С.; Lomakin, V.; Pukalov, V.; Dubodelov, V.; Goryuk, M.; Ломакин, В. Н.; Дубоделов, В. И.
Виконано аналіз основних параметрів дозування розплаву чавуну в металеві форми за допомогою магнітодинамічної установки МДН-6Ч. Розроблено принципову схему управління електромагнітними системами агрегату. Відпрацьовано технологію дозування і заливки металу в кокіль при виготовленні чавунних куль діаметром 40 і 120 мм. The analysis of the basic parameters of the dosage of molten iron in metal forms using the magnetodynamic installation MDN-6CH. A schematic diagram has been developed for controlling the electromagnetic systems of the unit. The technology of dosing and pouring metal into the chill mold has been developed in the manufacture of cast iron balls with a diameter of 40 and 120 mm. At the optimal casting temperature, the electrical parameters of the inductor (voltage Ui, current Ii, power Ri) were in the range Ui = 250-300 V, Ii = 480-520 A, Ri = 140-160 kW. When reducing the mass of metal in the crucible MDN-6CH using a control scheme made switching inductor from a voltage of 300 V to 250 V. The power was reduced by 15-20 kW, and the temperature of the metal remained within the tolerance of the technology of metal casting. Using the adopted dosing scheme, it became possible to cast metal at constant parameters of the electromagnetic system and the time of pouring. The technology of dispensing and pouring metal into the mold for the production of cast iron balls with a diameter of 40 and 120 mm was carried out at an inductor voltage of 300 V, and the electromagnet - 220 V. The initial level of metal on the drain socket was equal to 20 mm. The molding time of molds in the manufacture of balls with a diameter of 40 mm was 7.3 s, and balls with a diameter of 120 mm - 16.2 s. The operating time of the electromechanical actuator was set in the manufacture of balls with a diameter of 40 mm - 0.35 s, and balls with a diameter of 120 mm - 0.75s. The consumption of metal in the manufacture of balls with a diameter of 40 and 120 mm was in the range of 0.7-0.75 kg / s and 1.65-1.70 kg / s, respectively. The metal casting was carried out at temperatures of 1320-1340 ° C and 1360-1380 ° C. The dosage accuracy was determined by weighing the metal of the poured balls and the molding system of the mold. Mathematical processing of the results of the dosing showed that in the manufacture of balls with a diameter of 40 mm at a temperature of 1320 °C the error of dosing is 10-11%. With increasing iron temperature, the dosage error decreases and at a metal temperature of 1370 °C is 5-6%. In the manufacture of balls with a diameter of 120 mm at a temperature of iron 1330, the dosage error is 7-8%, and at a temperature of 1360 ° C - 3-4%. The study of the characteristics of the casting and dosing process of cast iron in the chill mold allowed us to develop the technology of casting cast iron melts, which provided the required metering accuracy and high productivity of the conveyor production of grinding bodies. Проведен анализ основных параметров дозирования расплава чугуна в металлические формы с помощью магнитодинамической установки МДН-6Ч. Разработана принципиальная схема управлення электромагнитными системами агрегата. Отработана технология дозирования и заливки металла в кокиль при изготовлении чугунных шаров диаметром 40 и 120 мм.
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.

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