Abstract
Medium- and high-Mn steels have excellent properties but are very difficult to be commercially produced because of the high content of some alloy elements. To enhance the understanding of the reaction between medium/high-Mn steel and refining slag which is significantly different from the conventional steels, steel and slag composition and the inclusions were investigated by equilibrium reaction between Fe-xMn (x = 5, 10, 15, and 20 mass pct) and CaO-SiO2-Al2O3-MgO top slag at 1873 K in the laboratory. Furthermore, the effect of Mn content on inclusion transformation and steel cleanliness was also explored. After slag–steel reaction, both contents of MnO in slag and Si in steel increased. Most MnO inclusions in master steel transformed to MnO-SiO2 and MnO-Al2O3-MgO. With the increase in Mn content, the amount share of MnO type inclusions decreased and that of MnO-Al2O3-MgO type increased. In addition, both the number density of observed inclusions and the calculated oxygen content in inclusions increased. Thermodynamic analysis indicates that the composition change of steel and slag and the transformation of inclusions are mainly the consequence of the reaction between Mn in molten steel and SiO2 and MgO in top slag. The dissolved Mn in medium/high-Mn steel presents a strong reactivity.
Highlights
Published: 28 July 2021In the past decades, with the increasing desire for energy saving and environmental protection, medium- and high-Mn steels, with Mn content higher than 3%, have garnered great attention from the automotive industry and researchers due to their outstanding mechanical properties, broad application prospects, and very high production difficulties.Some studies in metallurgy have been conducted to explore the mechanism, fundamental data, etc. for medium/high-Mn steels and to solve the problems met during the production of these steels
Pak [1] studied the thermodynamics of deoxidation equilibria and AlN formation in high-Mn- and high-Al-alloyed liquid steel
Studied reactions between Al and Mn in liquid steel and molten mold flux, which is closely related to the difficulties met in continuous casting of medium/high-Mn steels
Summary
Published: 28 July 2021In the past decades, with the increasing desire for energy saving and environmental protection, medium- and high-Mn steels, with Mn content higher than 3%, have garnered great attention from the automotive industry and researchers due to their outstanding mechanical properties, broad application prospects, and very high production difficulties.Some studies in metallurgy have been conducted to explore the mechanism, fundamental data, etc. for medium/high-Mn steels and to solve the problems met during the production of these steels. For medium/high-Mn steels and to solve the problems met during the production of these steels. Yan [2] and Yu [3] investigated metallurgical characteristics of refining slag for high-manganese steel. Studied reactions between Al and Mn in liquid steel and molten mold flux, which is closely related to the difficulties met in continuous casting of medium/high-Mn steels. With regard to the studies in the field of steelmaking, Liu [6] investigated the effect of CO2 and O2 mixed injection on Mn retention in high-Mn steel. Ladle slag is used in the production of medium/high-Mn steels. Because of the high content of alloys in these steels, the reactions between molten steel and top Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
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