In order to understand the vaporization behaviors of Mn in medium and high Mn steel grades during vacuum treatment

industrial experiments and thermodynamic calculations were carried out. The results indicate that Mn vaporization would lead to an obvious loss of Mn in steel

and the vaporization is strongly influenced by the steel temperature

Mn content and vacuum pressure. With the increase of temperature and Mn content in steel

the saturated vapor pressure of Mn increases

leading to an increasing vaporization of manganese. Meanwhile

lower vacuum pressure would also result in a stronger vaporization of dissolved Mn into gaseous Mn. The mass transfer of Mn in liquid steel would not be the controlling step of the vaporization process of Mn during VD and RH vacuum treatment.