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Foundry production
ArticleName Softening of sand mixtures on a liquid-glass binder as a result of thermal-oxidative destruction of a combined carbon-containing additive. Part 2
DOI 10.17580/chm.2023.02.11
ArticleAuthor N. A. Kidalov, N. V. Belova, A. A. Belov, A. S. Adamova

Volgograd State Technical University, Volgograd, Russia:
N. A. Kidalov, Dr. Eng., Prof., Head of the Dept. of Machinery and Technology of Foundry (MTF)
N. V. Belova, Lecturer, Dept. of MTF
A. A. Belov, Cand. Eng., Lecturer, Dept. of MTF, e-mail:
A. S. Adamova, Cand. Eng., Associate Prof., Dept. of MTF


The second part of the work is devoted to the study of the effect of the destruction of a combined carbon-containing additive on the softening of sand mixtures with a liquid glass binder in order to improve the knockout of casting cores from steel castings. The combined carboncontaining additive proposed in the first part of this work was introduced into the composition of the sand mixture with a sodium liquid glass binder. From the prepared mixtures, prototypes were made to determine the residual strength after calcination at temperatures corresponding to the heating of casting molds and cores when interacting with liquid steel. Next, the fractures of the samples after calcination at specified temperatures were selected to study the effect of the destruction of the additive on the formation of the sodium silicate film structure on the refractory quartz filler surface using scanning electron microscopy. It has been established that in order to ensure an effective reduction in the residual strength of the liquid-glass mixture after it is heated to the melting temperature of sodium silicate, it is necessary to form a discontinuous structure of the binder film by creating conditions that promote the continuous process of sodium silicate carbonization during the destruction of the carbon-containing additive. Pilot testing of the proposed composition of the mixture for the manufacture of foundry cores of steel casting was carried out. It is shown that casting cores from the mixture with the combined carbon-containing additive have improved knockout, while the destruction of the additive does not significantly affect the deterioration of the castings surface quality and the depth of the decarburized layer.

keywords Aqueous solution of sodium silicate, refractory filler, liquid-glass mixture, carboncontaining additive, sodium carbonate crystals, porosity, residual strength, knockout

1. Molding materials and mold technology: handbook. Edited by S. S. Zhukovskiy. Moscow: Mashinostroenie, 1993. 431 p.
2. Ryzhkov I. V., Tolstoy V. S. Physical and chemical bases for the formation of properties of mixtures with liquid glass. Kharkov: Visha shkola, 1975. 139 p.
3. Kidalov N. A., Adamova A. S., Grigoreva N. V. Selection of technological additives to the composition of the moulding mixtures based on water glass. International Journal of Cast Metals Research. 2021. Vol. 34. Iss. 3-6. pp. 162–168.
4. Kidalov N. А. The use of waste from chemical and metallurgical industries in the development of resource-saving technologies for the manufacture of steel castings: Dissertation … of Doctor of Engineering Sciences. Moscow, 2006. 352 p.
5. Song L., Liu W., Li Y., Xin F. Humidity-resistant inorganic binder for sand core making in foundry practice. China Foundry. 2019. No. 4 (16). pp. 267–271.
6. Guminskiy Yu. Yu., Rovin S. L. The use of a liquid glass binder modified with ultrafine materials. Liteynoe proizvodstvo. 2019. No. 11. pp. 17–20.
7. Leushin I. O., Leushina L. I., Balabanov I. P., Savin I. A. Production of moulding cores and waterglass mixtures using “dry ice” for steel and iron casting. CIS Iron and Steel Review. 2021. Vol. 21. pp. 34–37.
8. Rusevich О. А., Rovin S. L. Investigation of the influence of vacuum on the curing of mixtures with a silicate binder. Liteyshchik Rossii. 2022. Vol. 21. pp. 21–26.
9. Puzio S., Kamińska J., Major-Gabryś K., Angrecki M., Hosadyna-Kondracka M. Microwavehardened moulding sands with hydrated sodium silicate for modified ablation casting. Archives of Foundry Engineering. 2019. No. 2 (19). pp. 91–96.
10. Li Y., Zhao J., Du X., Sun Y., Song G., Miao H. The optimization of the properties of sodium silicate bonded ceramic sand by nano-oxide particles and ultrasonication. International Journal of Metalcasting. 2022. No. 1 (16). pp. 234–241.
11. Svinoroev Yu. A., Gutko Yu. I., Batyshev K. A., Semenov K. G. Softening additives of sand-liquidglass mixtures in the production of castings from iron and steel. Liteynoe proizvodstvo. 2021. No. 6. pp. 13–17.
12. Xin F., Liu W., Song L., Li Y. Modification of inorganic binder used for sand core-making in foundry practice. China Foundry. 2020. No. 5 (17). pp. 341–346.
13. Leushin I. O., Subbotin A. Yu., Geyko M. A. Mixture for making molds and rods. Patent RF, No. 2703637. 2019.
14. Finkelshtein A. B., Novozhilov N. Yu., Khusnullin D. V., Shefer A. A. The study of the core mixture on the Cordis-Anorgit binder composition. Liteynoe proizvodstvo. 2015. No. 4. pp. 15–18.
15. Kidalov N. A., Belova N. V., Belov A. A., Adamova A. S. Softening of sand mixtures on a liquidglass binder as a result of thermal-oxidative destruction of a combined carbon-containing additive. Part 1. Chernye metally. 2022. No. 12. pp. 24-29.
16. GOST 2138–91. Moulding sands. General technical specifications. Introduced 01.01.1993.
17. GOST 13078–81. Sodium liquid glass. Technical specifications. Introduced 01.01.1982.
18. GOST 7885–86. Technical carbon for rubber production. Technical specifications. Introduced 01.01.1988.
19. Borovskiy Yu. F., Shatskikh M. I. Molding and core sands. Leningrad: Mashinostroenie: Leningradskoe otdelenie, 1980. 86 p.
20. GOST 23409.6–78. Molding sands, molding and core sand mixtures. Method for determination of gas permeability. 1985. 5 p. Introduced: 01.01.1980.
21. Novik F. S., Arsov Ya. B. Optimization of metal technology processes by methods of planning experiments. Moscow: Mashinostroenie, 1980. 304 p.
22. Vereshchagin V. I., Borilo L. P., Kozik A. V. Physical and chemical study of porous composite materials based on SiO2. Khimiya i khimicheskaya tekhnologiya. 2003. Vol. 46. No. 8. pp. 138–140.
23. GOST 977–88. Steel castings. General technical specifications. Introduced 01.01.1990.
24. GOST 25142–82. Surface roughness. Terms and definitions. Introduced 01.01.1983.
25. GOST 1763–68. Steel. Methods of determination of decarbonization layer depth. Introduced 01.01.1970.
26. Metalworker's Handbook. In 5 volums. Vol 2. Edited by А. G. Rakhshtadt, V. А. Brostrem. Moscow: Mashinostroenie, 1976. 720 p.
27. Vasin Yu. P., Itkis Z. Ya. Oxidizing mixtures in the conveyor production of steel castings. Chelyabinsk: Yuzhno-Uralskoe knizhnoe izdatelstvo, 1973. 153 p.

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