Ural Steel, Novotroitsk, Russia
V. V. Lazeev, Head of Sales Engineering Support Оffice, New Types of Products Dept., e-mail: v.lazeev@uralsteel.com
O. P. Vereshchagina, 1^st Category Engineer, New Types of Products Dept., e-mail: o.vereshchagina@uralsteel.com
D. V. Nizhelskiy, Deputy Technical Director - Head of the New Types of Products Dept., e-mail: d.nizhelskiy@uralsteel.com
K. S. Skokov, Chief Specialist, Foundry and Electric Steelmaking Production, New Types of Products Dept., e-mail: k.skokov@uralsteel.com
L. G. Evsina, Chief Specialist, Metal Science, New Types of Products Dept., e-mail: l.evsina@uralsteel.com

Foundry Plant of JSC Ural Steel is a foundry with more than half a century of history. In 2024 the plant celebrated its 65th anniversary. In the small casting area of the Foundry Plant the manufacturing technology of castings from gray cast iron weighing up to 6 tons according to GOST 1412-85 has been mastered starting from its foundation. In 2018 the Foundry Plant arranged a large-size casting area for the production of steel metallurgical utensils. In order to extend the product mix of the large-size area it was decided to master the manufacturing technology of large-size castings from gray cast iron. Taking into account the peculiarities and production capacities of the Plant, the experience and technology of large-size steel castings production was taken as the basis for developing the technological chain for the manufacture of gray cast iron castings. In order to achieve the specified chemical composition of the semi-finished product, additional operations were considered and tested in the Steelmaking Plant of the Integrated Iron and Steel Plant: decarburization of hot metal from the Blast Furnace Plant to a specified carbon content (1); additional alloying of the melt with silicon and manganese containing materials (2); correction of the hot metal chemical composition during secondary refining in the ladle furnace (3). The first experimental work resulted in the production of large-size products weighing from 35 to 114 t with a wall thickness of more than 300 mm, with a chemical composition corresponding to the SCHI-2 grade. The microstructure and mechanical properties of the produced castings were investigated, the casting defects of the castings were analyzed and measures were developed and implemented to eliminate them.

1. Korolev S. P. Features and prospects of manufacturing castings from cast iron with vermicular graphite. Liteynoe proizvodstvo. 1998. No. 12. pp. 37–39.
2. Zakharchenko E. V., Levchenko Yu. N., Gorenko V. G., Varenik P. A. Castings from cast iron with globular and vermicular graphite. Kiev : Naukova dumka, 1986. 247 p.
3. GOST 1412–85. Flake graphite iron for castings. Grades. Introduced: 01.01.1987.
4. STO 13657842-62–2023. Electric steel making iron grades SChI-1 and SChI-2 for production of large-sized castings. Specifications. Novotroitsk : Uralskaya Stal, 2023. 8 p.
5. GOST 805–95. Steel making pig iron. Specifications. Introduced: 01.01.2000.
6. Sergeev N. N., Gvozdev A. E., Starikov N. E. Technology of metals and alloys. Moscow : Infra-Inzheneriya, 2020. 480 p.
7. Bykov O. Secondary refining of melts. Methodological guidelines for studying the discipline. Pavlodar : PSU named after S. Toraygyrov, 2006. 41 p.
8. Guzman V. M., Yasnitsky L. N., Burdakov K. A. The influence of green strength of molding mixture on the level of castings rejected due to “clogging”. Liteynoe proizvodstvo. 2024. No. 12. pp. 13–16.
9. Gileva L. Yu., Kaplun L. I., Zagaynov S. A. Cast iron metallurgy: textbook. Edited by S. A. Zagaynov. Yekaterinburg : Izdatelstvo Uralskogo universiteta, 2021. 128 p.
10. GOST 24648–90. Pig iron for castings. Sampling and making the specimens for mechanical testing. Introduced: 01.07.1992.
11. GOST 27208–87. Cast iron castings. Methods of mechanical testing. Introduced: 01.01.1988.
12. GOST 3443–87. Cast iron castings with graphite of different form. Methods of structure determination. Introduced: 01.07.1988.
13. Nagaoka K., Souma M. Irreversible carbon diffusion in growth of cast iron. MRS Proceedings. 1984. Vol. 34. pp. 355–364.
14. Jabbari Behnama M. M., Davamia P., Varahrama N. Effect of cooling rate on microstructure and mechanical properties of gray cast iron. Materials Science and Engineering. А. 2010. Vol. 528. pp. 583–588.