Einfluss ausgewählter Spurenelemente auf das Benetzungsverhalten im System Stahl-Einschluss-Feuerfest

In order to achieve a reduction of carbon dioxide emissions in the steel industry, the electric arc furnace finds increasing use. With this production route, steel scrap plays a decisive role as feedstock. However, scrap is often contaminated with undesirable trace elements which are difficult or impossible to remove. While the effect of these elements on the mechanical properties is well studied, there is little knowledge about their influence on the wetting behavior of steel. In secondary metallurgical treatments, a high wetting angle between the melt and non-metallic inclusions is preferred to promote separation of the inclusions into the slag. In order to investigate the influence of copper, molybdenum and tin on the wetting behavior, a series of drop shape analyses on medium carbon steel samples alloyed with those elements was performed in this work. The wetting angles of the samples were determined on both alumina and zirconia at a temperature of 1600 °C and over a holding time of 30 minutes. It was shown that these elements led to a reduction of the wetting angle on both substrates compared to the angle of the not modified steel. The reduction of the angle was more pronounced on zirconia. For some specimens, the decrease in the wetting angle was so severe that the deposition behavior of non-metallic inclusions can be expected to be influenced. A more pronounced decrease of the wetting angle with increasing trace element contents could not be observed. Metallographic examinations of the samples showed no chemical change of the droplets or the substrate. Furthermore, no formation of a reaction layer was observed.