STUDIES IN DEVELOPMENT OF CLEAN STEELS - PART 1 - MODELING ASPECTS

Inclusion engineering models currently use thermodynamic models to des cribe slag-metal equilibria at various processing stages. Often, howev er, the predicted slag-derived inclusions do not compare well with mea sured compositions and reoxidation or solute reactions must be include d for calculated results to agree with those observed. Clearly, the no n-metallic inclusion population in the final product will be the resul t of a whole series of interactive events involving local equilibria a nd process kinetics. To understand the individual mechanisms that take place during inclusion generation, their interaction with steel, refr actories, slag, and atmosphere, and their removal from or retention in the steel, it is necessary to account for the time dependent interact ions that occur during steel processing. This holistic approach requir es a step by step account of the changing element concentration and te mperature gradients in the steel, taking into account the effect of fl uid flow and stability of the resulting inclusions. As a first step, t wo- and three-dimensional mathematical modelling of the fluid flow and the temperature and concentration gradients within a steel ladle duri ng tapping, alloy addition, and stirring operations has been carried o ut and the local inclusion compositions within the steel predicted. IS /1391a (C) 1998 The Institute of Materials.