Development and mastering of technology for production of large-sized cast products from gray cast iron in the conditions of JSC Ural Steel

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.