Study on Mn Volatilization Behavior During Vacuum Melting of High-manganese Steel

As an alloying element in steel, manganese can considerably enhance the mechanical properties of structural steel. However, the Mn volatilisation loss in vacuum melting is severe because of the high saturated vapour pressure, resulting in an unstable Mn yield and Mn content fluctuation. Therefore, a systematic study of the volatilisation behaviour of Mn in vacuum melting is required to obtain a suitable Mn control process to achieve precise control of Mn composition, thereby providing a theoretical basis for industrial melting of high-Mn steel. In order to explore the Mn volatilization behavior, the volatilization thermodynamics and volatilisation rate of Mn, as well as the influence factors are discussed in this study. The results shows that Mn is extremely volatilised into the vapour phase under vacuum, the equilibrium partial pressure is closely related to Mn content and temperature. With an increase in the Mn content, a higher C content has a more obvious inhibitory effect on the equilibrium partial pressure of Mn. The maximum theoretical volatilisation rate of Mn shows a linear upward trend with an increase in Mn content. However, a higher C content has a more obvious effect on the reduction of the maximum theoretical volatilisation rate with the increase of Mn content. This study provides an improved understanding of Mn volatilisation behaviour as well as a theoretical foundation for consistent Mn yield control during the vacuum melting process of high-Mn steel.