Evaporation of Manganese, Copper and Tin from Molten Iron under Vacuum

The rate of evaporation of alloying elements from Fe-Mn, Fe-C-Mn, Fe-Cu and Fe-Sn alloys in vacuum induction melting at 1600℃ has been investigated. The evaporation of the alloying elements took place according to the first order kinetics for initial 10～20 minutes and the evaporation constants were obtained. Following R.G. Ward, the ratio of concentration at surface to that in bulk for each alloying element in molten iron was obtained from the evaporation constants. The evaporation coefficient α and the distribution coefficient k were measured. The experimental values of α and k are well explained by introducing the concentration ratio into the theoretical relations of α and of k, which were derived by M. Olette, and by W.A. Fischer and M. Derenbach, respectively