Evaporation of Trace Bismuth during Vacuum Melting of Steel

The result shows that the rate of bismuth recovery reachs 7.54% by adding pure bismuth to liquid steel under the experimental condition.The evaporation process of trace bismuth is controlled by transport in both the metal boundary layer and the evaporation from the pool surface, in which the transport coefficient K₂₃ is at the order magnitute of 10^-2cm/s.The experimental formulas to calculate K₂₃ and bismuth concentration in molten steel have been gained.The effect of covering slag on bismuth evaporation has also been studied.