Influencing mechanism of (V, Ti)@(C, N) compounds on the viscosity of hot metal

Abstract

The precipitation of the (V, Ti)@(C, N) compounds, for example, VC, VN, TiC and TiN, in the hot metal during the ironmaking process may result in high viscosity of the hot metal and cause a negative impact on the process. How to control the precipitation of the (V, Ti)@(C, N) compounds is a significant issue for the high-efficient ironmaking. In this paper, the precipitation behaviour of the (V, Ti)@(C, N) compounds and its effect on the viscosity of the hot metal were investigated. The theoretical analysis results show that the precipitation temperature of the (V, Ti)@(C, N) compounds increases with the increasing content of vanadium, titanium, silicon and manganese, while it decreases with the that of sulphur and phosphorus in hot metal. Additionally, the viscosity-measuring was carried out by a self-developed melt viscometer, and the results show that the viscosity of the hot metal can be affected significantly by the vanadium content. As the vanadium content exceeds 0.3 wt.%, the viscosity of the hot metal increases sharply with the increasing of vanadium content, which will have a serious impact on the fluidity of the hot metal. Furthermore, the precipitation product in the hot metal was confirmed to be the (V, Ti)@(C, N) compounds by using the scanning electron microscope and the energy dispersive x-ray spectroscopy, which proved that the compounds mainly consist of the V, Ti, C and N elements.