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As global steel production shifts from conventional carbon steels to more advanced materials, cerium has emerged as a key microalloying element. It effectively binds with sulfur, phosphorus, and oxygen, reducing harmful impurities in the iron matrix. Additionally, cerium refines the austenite grain during casting, improving fluidity and reducing metal porosity, which ultimately enhances the mechanical properties of ferrous metallurgy products.

Supported by the Priority-2030 academic leadership program, the research team of Belgorod National Research University (BelSU), led by Ivan Nikulin, has pioneered an economical technique for producing high-strength microalloyed steels. Their method uniquely employs cerium carbide for alloying, which offers properties that are either comparable to or even superior to those achieved with metallic cerium. Key advantages include improved tensile and yield strength, attributed to the fine-grained and equiaxed structure formed after casting and the effective removal of harmful impurities.

Notably, cerium carbide is 40-50% cheaper than its metallic counterpart. While other modification methods utilizing cerium, ferrocerium, and mischmetal exist, they face challenges due to cerium's low melting point (798 °C). This low temperature can lead to increased residual vapour pressure in a vacuum, causing unreacted cerium to evaporate and necessitating the use of larger amounts of expensive alloying agents. In contrast, the BelSU method allows cerium carbide to remain stable during the melting process, gradually reacting with harmful impurities in the liquid metal without the risk of splashing or pyroelectric effects. With a melting point exceeding 2200 °C, cerium carbide reacts calmly at the melting temperatures of steels and cast irons (ranging from 1147 to 1530 °C).

“The method we proposed ensures complete interaction between the product and the liquid metal, allowing for a nearly tenfold refinement of the cast structure of steel, significantly enhancing the quality of the final product,” explained Ivan Nikulin.

The modification process involves placing cerium carbide at the bottom of the melting unit, comprising 0.01-0.18 wt.% of the total metal weight. Powdered steel, with particle sizes between 20 and 80 microns, is then added over the carbide. The mixture is melted at 1500 °C in a bulk melting unit under a pressure of 0.5⋅10³ mbar within an argon atmosphere or vacuum for five minutes until the cerium carbide fully dissolves.

This proposed method is versatile, enabling remelting in both argon atmospheres and vacuum conditions, as cerium carbide exhibits minimal evaporation at typical melting temperatures for ferrous metallurgy products. Currently, BelSU scientists are exploring opportunities for scaling and optimizing this technology, which has already garnered interest from industrial partners. The uniqueness and innovation of this method are protected by a Russian patent.