DOI: https://doi.org/10.32515/2409-9392.2018.31.66-74

Research of the Solidification Process and Prediction of the Structure of Cast Cast-Iron Grinding Bodies

Viktor Lomakin, Vasyl Klymenko, Viktor Pukalov, Olexandr Kuzyk, Viktor Dubodelov, Maxym Goriuk

About the Authors

Viktor Lomakin, Associate Professor, PhD in Technics (Candidate of Technics Sciences), Central Ukrainian National Technical University, Kropyvnytskiy, Ukraine, E-mail: vik284333@gmail.com

Vasyl Klymenko, Professor, Doctor in Technics (Doctor of Technics Sciences), Central Ukrainian National Technical University, Kropyvnytskiy, Ukraine

Viktor Pukalov, Associate Professor, PhD in Technics (Candidate of Technics Sciences), Central Ukrainian National Technical University, Kropyvnytskiy, Ukraine

Olexandr Kuzyk, PhD in Technics (Candidate of Technics Sciences), Central Ukrainian National Technical University, Kropyvnytskiy, Ukraine, E-mail:kuzykov1985@gmail.com

Viktor Dubodelov, Professor, Doctor in Technics (Doctor of Technics Sciences), Physiko-Technologikal Institute of Metals and Alloys, Kyiv, Ukraine

Maxym Goriuk, PhD in Technics (Candidate of Technics Sciences), Senior Research, Physiko-Technologikal Institute of Metals and Alloys, Kyiv, Ukraine

Abstract

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.

Keywords

сylinder for crushing, cast ball, alloyed cast iron, chromium, metallic form, solidification, structure, modeling

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References

Bestuzhev, N.I. & Korolev, S.P. (1999). Grafitizirovannyj belyj chugun – perspektivnyj material dlja meljushhih tel [Graphitized white cast iron is a promising material for grinding media]. Litejnoe proizvodstvo – Foundry, 3, 20-21.

Balandin, G.F. (1976). Osnovy teorii formirovanija otlivki [Fundamentals of the casting formation theory]. Moscow: Mashinostroenie.

Korn, G. & Korn, T.(1978). Spravochnik po matematike [Math Handbook]. Moscow: Nauka.

Vejnik, A.I (1960). Teorija zatverdevanija otlivki [Theory of Casting]. Moscow: Mashinostroenie.

Zhuhovickij, A.A. & Shvarcman, L.A. (1987). Physical chemistry. C.I. Popelja (Ed.). Moscow: Metallurgija.

Dubodelov, V.I., Pogorskij, V.K., Kropivnyj, V.N. & Lomakin, V.N. (1999). Chislennoe issledovanie kinetiki zatverdevanija meljushhih tel v metallicheskih formah s estestvennym vozdushnym ohlazhdeniem [Numerical study of the kinetics of hardening of grinding bodies in metal forms with natural air cooling]. Zbirnyk naukovykh prats' Kirovohrads'koho derzhavnoho tekhnichnoho universytetu – Collection of scientific works of Kirovograd State Technical University, 4, 5-10.

Girshovicha, G.F. (Eds.). (1978). Cast Iron Handbook. Leningrad: Mashinostroenie.

GOST Style Citations

  1. Бестужев Н.И. Графитизированный белый чугун – перспективный материал для мелющих тел [Текст] / Н.И. Бестужев, С.П. Королев // Литейное производство. – 1999. – №3. – С. 20-21.
  2. Баландин Г.Ф. Основы теории формирования отливки [Текст] / Г.Ф. Баландин. – М: Машиностроение, 1976. – 328 с.
  3. Корн Г. Справочник по математике [Текст] / Г. Корн, Т. Корн. – М: Наука, 1978. – 832 с.
  4. Вейник А.И. Теория затвердевания отливки [Текст] / А.И. Вейник. – М: Машиностроение, 1960. – 435 с.
  5. Жуховицкий А.А. Физическая химия [Текст] / А.А. Жуховицкий, Л.А. Шварцман; под ред. C.И. Попеля. – М.: Металлургия, 1987. – 688 с.
  6. Дубоделов В.И. Численное исследование кинетики затвердевания мелющих тел в металлических формах с естественным воздушным охлаждением [Текст ] / В.И. Дубоделов, В.К. Погорский, В.Н. Кропивный, В.Н. Ломакин // Збірник наукових праць Кіровоградського державного технічного університету. – 1999. – №4. – С.5-10.
  7. Справочник по чугунному литью [Текст] / под ред. Г.Ф. Гиршовича. – Л: Машиностроение. – 1978. – 758 с.
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