Surface Tension of Liquid Fe–N–O–S Alloy

Abstract

Surface tension and composition of gas–iron alloy interphase were calculated for Fe–N–S–O system using the modified form of Butler's equations and the derived values of the surface interaction parameters of the system. The calculated values are found to be in very good agreement with published experimental data in literature. Simulations showed that if contents of strong surface active elements such as sulphur and oxygen are low, nitrogen also works as a surface active element and decreases surface tension of melt. According to the calculations, the surface tension of steel in traditional BOF process changes from 1.73 to 1.1 N/m. Furthermore, it decreases due to high alloying of nitrogen and sulphur also during secondary metallurgical treatments although decrease is not as remarkable as during decarburization. Hence the surface tension cannot be assumed to be constant especially when fluid flows of BOF were studied.