Volgograd State Technical University (Volgograd, Russia):

N. I. Kidalov, Dr. Eng., Prof., Head of Dept. “Machines and Technology for Foundry Production”
N. I. Gabelchenko, Cand. Eng., Associate Prof.
A.A. Belov, Post-graduate student
A. I. Savchenko, Applicant
E-mail (common): mitlp@vstu.ru

N. Yu. Gulakov, head of the technological bureau of the blast-furnace shop of JSC EVRAZ NTMK, M. V. Polovets, engineer-technologist of the technical department of JSC EVRAZ NTMK, A. D. Martyukov, head of the industrial technology department of JSC EVRAZ NTMK participated in the preparation of the article.

The studies are devoted to the selection of carbon-containing additives introduced into the composition of molding sand-clay mixtures to control the cooling rate of castings in the mold due to their destruction at various temperatures and the time of heating the mold. The analysis of the properties of the following additives is presented: foundry coal coke, coal-tar electrode pitch, M-100 heating oil, M-200 wood flour, wastes of contact cleaning of oils. To study exothermic carbon-containing additives, the Q-1500D derivatograph from MOM, Hungary was used, with which mass changes (thermogravimetric analysis) and processes accompanied by heat generation or absorption (differential thermal analysis) were recorded simultaneously with heating to temperatures of their destruction and higher. Exothermic carbon-containing additives were heated to temperatures comparable to the ones of the facing layer of the mold upon contact with molten iron during pouring. In view of the different speed of mold heating during casting of shaped castings, studies of exothermic carbon-containing additives were carried out at different heating rates: 2.5; 5; 10, 20 °C/min. This allowed to analyze the dynamics of changes in mass loss and thermal effect. To prevent the formation of gas defects in the casting, the gas generating ability of additives during heating to 1250 °C was determined according to GOST 23409.12–78. As a result of comparative studies, an additive was selected combining properties that contribute to the slowdown in the rate of crystallization and cooling of cast iron castings in the sand-clay mold. It is shown that the additive combining the maximum ability to lose the mass and generate the heat at the same time the minimum gas generating ability is M-100 fuel oil. In the course of the work, experimental equipment was designed and manufactured, which allows both experimental and control castings to be poured. To regulate the cooling rate, it was decided to introduce the studied exothermic carboncontaining additive, M-100 heating oil, into the facing molding mixture, which, when ignited, heats the mold, slowing down the solidification process of the cast iron. It is shown that the use of controlled cooling can significantly increase the tensile strength of cast iron without introducing additional alloying elements into its composition. 

1. Kostyleva L. V., Ilinskiy V. А., Gabelchenko N. I., Pozharskiy А. V., Gulevskiy V. А. The study of cooling modes of cast iron castings. Liteynoe proizvodstvo. 1999. No. 2. pp. 9–11.
2. Kidalov N. А., Gabelchenko N. I., Belov А. Аl., Savoskin V. А., Kravchenko А. S. The selection of exothermic carbon-containing additives used to control the cooling rate of iron castings. Izvestiya VolGTU. Seriya: Problemy materialovedeniya, svarki i prochnosti v mashinostroenii. 2019. No. 4. pp. 92–95.
3. Ilinskiy V. A., Gulevskiy V. A., Kostyleva L. V., Gabelchenko N. I., Pozharskiy A. V. Method for making high quality iron castings. Patent RF, No. 2156673. Applied: 12.05.1999. Published: 27.09.2000.
4. Bogachev I. N., Dubinin N. P., Egorenkov I. P. et. al. Foundry Handbook: Iron Casting; general edition N. N. Rubtsov. Moscow: Mashgiz, 1961. 774 p.
5. Tadesse A., Fredriksson H. Volume change during the solidification of grey cast iron: its relation with the microstructural variation, comparison between experimental and theoretical analysis. International Journal of Cast Metals Research. 2017. Vol. 30, Iss. 3. pp. 159–170.
6. Hong Nga P. T., Ngoc Thien T., Josepha Pritadewi P., Phuong V. N. Y. Research on Factors Influencing the Formation Graphite and Effect of Graphite on Mechanical Properties of Grey Cast Iron. International Conference on System Science and Engineering (ICSSE), Dong Hoi, Vietnam, 2019. pp. 619–629.
7. Korovin V. А., Leushin I. Relation between modification and graphitization processes in cast iron. Chernye Metally. 2010. No. 7. pp. 30–32.
8. Glicksman M. E. Principles of solidification, an introduction to modern casting and crystal growth concepts. New York, Springer-verlag, 2010.
9. Christian J. W. The theory of transformations in metals and alloys. Oxford, Elsevier Science Ltd. 2002. 1200 p.
10. Mingguo X., Changan Z. Jianxin Z. Bidirectional impact of undercooling on eutectic structural formation of hypoeutectic grey iron and its physical connotation. Materials Research Innovations. 2015. Vol. 19, Iss. 5. pp. S5157–S5162.
11. Górny M., Tyrała E. Effect of cooling rate on microstructure and mechanical properties of thin-walled ductile iron castings. J. Mater. Eng. Perform. 2013. Vol. 22, Iss. 1. pp. 300–305.
12. Vdovin K. N., Gorlenko D. A., Zavalischin A. N. Study of the effect of isothermal holding on parameters of graphite phase in indefinite chromium-nickel cast iron alloyed by nitrogen and vanadium. CIS Iron and Steel Review. 2019. Vol. 17. pp. 30–33.
13. Berg P. P. Molding materials. Moscow: Mashgiz, 1963. 408 p.
14. Kukuy D. М., Skvortsov V. А., Andrianov N. V. Theory and technology of foundry: in 2 parts. Part 1. Molding materials and mixtures: tutorial. Moscow: INFRA-М, 2011. 384 p.
15. Trukhov А. P., Sorokin Yu. А., Ershov N. Yu. et. al. Foundry technology: Sand casting: tutorial edited by A.P. Trukhov. Moscow: Akademiya, 2005. 528 p.
16. Technical Specification No. 38.30112–83. Wastes of petroleum processing. Worked forming clay. - Introduced 12.01.1993.
17. GOST 16361–87. Wood floor. Specifications. Introduced: 01.01.1990.
18. GOST 10585–2013. Petroleum fuel. Fuel oil residue. Specifications. Introduced: 01.01.2015.
19. Technical Specification No. 0761-028-00187852–2015. Foundry coal coke produced by OJSC Moskoks. 2010.
20. Gost 10200-83. Coal tar electrode asphalt. Technical Specification. Introduced: 01.01.1985.
21. GOST 23409.12–78. Molding and core sand mixtures. Method for determination of gas formation. Introduced: 01.01.1980.
22. GOST 2138–91. Moulding sands. General specifications. Introduced: 01.01.1993.
23. GOST 28177–89. Moulding bentonite clays. General specifications. Introduced: 01.01.1991.