2007 Volume 48 Issue 12 Pages 3079-3087
Copper is one of the main residual elements in steel, especially in recycled scrap steel. Sulfur and phosphorus are two of the main impurities in steel, and it may result in a large emission of slag and CO2 to remove them from steel. Utilization of these elements has been an important and difficult matter for metallurgist. In the present paper, the as-cast steels containing different concentrations of copper, sulfur and phosphorus are prepared by strip casting process or laboratory rapid solidification process. The effect of phosphorus addition on sulfide precipitation is investigated and discussed with respect to the morphology, size, and composition of sulfide. Both experimental results and mathematical calculation showed that the addition of phosphorus retards the sulfide precipitation at high temperature, promotes more copper bearings and smaller sulfides precipitation at low temperature. On the other hand, sulfide precipitates are shown to reduce the micro-segregation degree of phosphorus in steel, which may be because some phosphorus dissolves in sulfide and sulfide particles provide more interfaces for phosphorus to distribute.
