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Continuous casting and foundry production
ArticleName The use of technological additives of carbonates and ammonium bicarbonates in resource-saving technology of precision steel casting
ArticleAuthor L. I. Leushina, I. O. Leushin, M. A. Larin, S. V. Plokhov

Nizhniy Novgorod State Technical University (Nizhniy Novgorod, Russia):

L. I. Leushina, Cand. Eng., Associate Prof., the Chair “Metallurgical technologies and equipment”
I. O. Leushin, Dr. Eng., Prof., Head of the Chair “Metallurgical technologies and equipment”, E-mail:;
M. A. Larin, Cand. Eng., Associate Prof., the Chair “Metallurgical technologies and equipment”
S. V. Plokhov, Dr. Eng., Prof., Chair “Nanotechnologies and biotechnologies”


For reasons of economic feasibility, some domestic enterprises practice a duplex scheme for manufacturing multilayer shell molds for investment casting, which involves using expensive hydrolyzed ethyl silicate or finished binder for the internal, working, shell layers, and relatively cheap and environmentally friendly liquid glass for the outer, reinforcing layers. However, the reduced crack resistance of the outer layers of such forms often does not guarantee the stability of the quality of the obtained castings during the calcination of the shells and the subsequent pouring of the metal melt, which is especially unacceptable for the production of critical products. In this regard, enterprises are often forced to resort to an increase in the number of working layers of the shell or to the use of an energy-intensive technological scheme for casting casting molds in a support filler poured into special flasks from expensive heat-resistant material. The paper presents a solution to the problem of choosing an economical technological option to increase the crack resistance of the outer layers of the shell form on liquid glass, applicable to the conditions of the current production and not requiring significant expenditures during development. The known curing mechanisms of molding and core compositions based on liquid glass are analyzed, the conclusion is drawn that the dehydration is insufficient as the only curing mechanism for the outer layers of shells formed on the basis of a liquid binder, and the hypothesis of an increase in crack resistance of the liquid glass composition when several curing mechanisms are combined is formulated. As a working curing option for combining with dehydration, a CO2-process was chosen, the physics and chemistry of which are discussed in detail in the article. Variants of non-deficient substances were evaluated that could play the role of a technological additive to the mold material during its manufacture at the base enterprise while simultaneously performing the most important function of the supplier of carbon dioxide. As a result, carbonate and ammonium bicarbonate were selected, the use of which allows to provide the required level of characteristics of the casting mold. A pilot test of a solution to a problem successfully confirmed its effectiveness and acceptability for existing production.

keywords Resource-saving technology, steel investment casting, shell mold, crack resistance, technological additives, ammonium carbonate, ammonium hydrocarbonate

1. Genzler C. Schnelltrocknende Wasserschlichte. Giesserei. 2016. No. 4. S. 82–83.
2. Festigkeitsbestimmung von Feingusskeramik – schnell und präzise. Giesserei. 2018. No. 6. S. 54–57.
3. Chen X., Sun B., Li F., Xiao L., Yu J. Research status of the interface reactions between superalloys and ceramic materials in investment casting. Journal of Special Casting & Nonferrous Alloys. 2016. Vol. 36, No. 8. pp. 844–848.
4. Znamenskij L. G., Ivochkina O. V., Varlamov A. S. Economical ceramic molds in investment casting. Materials Science Forum. 2016. Vol. 843. pp. 208–212.
5. Leushin I. O., Leushina L. I., Koshelev О. S. Innovative technology of manufacture of shell ceramic moulds for fabrication of castings of removable models. Chernye Metally. 2018. No. 5. pp. 25–28.
6. Nikiforov S. А., Nikiforov А. P., Root Е. P. Increasing refractory properties of liquid glass ceramics of combined shells at investment casting. Proceedings of the 7th Congress of founders of Russia. Vol. 2. Novosibirsk: Izdatelsky dom «Istoricheskoe nasledie Sibiri», 2005. pp. 95–99.
7. Kidalov N. А. Selection of technological additives in compositions of liquid glass mixtures. Liteyshchik Rossii. 2006. No. 7. pp. 37–41.
8. Makarevich А. P., Kocheshkov А. S., Lyuty R. V. Ceramic moulds for investment casting with low-modulus liquid glass. Liteynoe proizvodstvo. 2005. No. 10. pp. 20–22.
9. Ivanov V. N., Kazennov S. А., Kurchman B. S. et. al. Investment casting: edited by Shklennik Ya. I., Ozerov V. A. Moscow: Mashinostroenie, 1984. 408 p.
10. Leushin I. O., Maslov К. А. On some methods to increase fabricability of cores based on liquid glass binder. Theory and technology of metallurgical production: Trans-regional collection of scientific works. Edited by Kolokoltsev V. M. Iss. 10. Magnitogorsk: GOU VPO «MGTU», 2010. pp. 121–126.
11. Grachev А. N., Leushin I. О., Leushina L. I. Development of compositions o exothermic mixtures for steel and iron castings using wastes of thermal production. Chernye Metally. 2018. No. 2. pp. 39–43.
12. Available at: prochnost_liteinix_form/osnovi_texnologii_liteinix_form/30 (accessed: 18.11.2018).
13. Garanin V. F., Firsov V. G., Murkina А. S. Optimization of shell drying modes for investment casting. Liteynoe proizvodstvo. 1991. No. 5. pp. 28–29.
14. Serebryakov S. P., Redkin I. А., Shatulsky А. А. Improvement of the technology for investment casting mould drying. Zagotovitelnye proizvodstva v mashinostroenii. 2017. Vol. 15, No. 1. pp. 3–5.
15. Zhiltsov N. P., Kidalov N. А., Grebnev Yu. V. Study of knocking-out ability of ceramic moulds at investment casting. Zagotovitelnye proizvodstva v mashinostroenii. 2017. Vol. 15, No. 7. pp. 291–293.
16. Tkachenko S. S., Emelyanov V. О., Martynov К. V., Kuznetsov R. V. On formation of contact surface at investment casting. Liteynoe proizvodstvo. 2017. No. 1. pp. 35–37.
17. Illarionov I. Е. Application of fabrication technology for metal phosphate binders, core sands and moulding mixtures on their base. Chernye Metally. 2018. No. 4. pp. 13–19.
18. Illarionov I. E., Gilmanshina T. R., Kovaleva A. A., Kovtun O. N., Bratukhina N. A. Destruction mechanism of casting graphite in mechanical activation. CIS Iron and Steel Review. 2018. Vol. 15. pp. 15–17.
19. Technical specification No. 6-02-1-046-95 Binders.
20. GOST 9077-82 Ground pulverized quartz. General specifications. Introduced: 01.07.1983.
21. GOST 9070–75 Viscosimeter for determination of relative viscosity of paint and lacquer materials. Specifications. Introduced: 01.01.1977.
22. Leushina L. I., Ulyanov V. A., Leushin I. O. Method of producing multilayer investment shell casting moulds. Patent RF No. 2532764. Applied: 22.10.2013. Published: 10.11.2014. Bulletin No. 31.
23. GOST 2138-91. Moulding sands. General specifications. Introduced: 01.01.1993.
24. GOST 977-88. Steel castings. General specifications. Introduced: 01.01.1990.

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