2003 Volume 43 Issue 10 Pages 1487-1494
The thermodynamic analysis of oxygen solutions in Fe-Ni melts containing manganese and silicon has been carried out. The deoxidation power of manganese essentially increases with the nickel content in melt. The solubility curves pass through a minimum, which shifts to lower manganese contents, as nickel content in melt increases. For alloys containing more than 50-60% nickel, the minimal oxygen concentrations are obtained at manganese content equal to 1-1.5%, the further increase of manganese concentration results in an increase of oxygen content. Silicon deoxidation power also increases with the increase of nickel content in melt, but not so sharply as in the case of manganese. In the range of silicon contents considered, no minimum was observed in oxygen solubility curves. Thermodynamics of oxygen, manganese and silicon solutions in the Fe-40%Ni melts has been studied experimentally in a temperature range of 1 823-1 923 K. With temperature drop, deoxidation power of both manganese and silicon increases. In the Fe-40%Ni melts in both cases it is higher than in iron but lower than in nickel. Dependence of oxygen concentration on manganese and silicon contents is expressed by empirical equations. Upon combined deoxidation with manganese and silicon, it is possible to obtain lower oxygen concentrations in metal, in comparison with separate deoxidation due to decreased activities of manganese oxide and silica.
