Today's steelmaking is constantly challenged by increasing quality demand and the term “Clean Steel” has gained more and more ground. In many steel plants, slag carry over from the ladle into the tundish is negatively influencing the quality of steel. When the casting starts, the steel flows undisturbed through the defined bore of the seating block and inner nozzle, the whole cross section of the bore filled with steel, but due to the vortex-effect a slag core appears in the centre of the steel stream towards the end of the casting. The solution is the Clean Steel Block, a combination of seating block and purge plugs in the corners. First trials in different steel plants indicated that the installation of the Clean Steel Block will constantly suppress the vortex-effect and increases the quality of the semi-finished product.