Application of Thermodynamics in Mitigating Wire Rod Chipping During Hot Rolling of Continuously Cast Steel Billets

摘要

Surface peeling or chipping of wire rod has been one of the serious problems of hot rolling of continuously cast low carbon steel billets. This led to frequent interruption in the rolling mill production besides impairing the surface quality of the finished wire rods. Metallographic examination of wire rod samples revealed the problem was largely due to presence of gas porosity or fine blow holes close to the surface of the cast billets. Higher dissolved gases in liquid steel can lead to the formation of gas porosity during initial stage of liquid steel solidification in billet casting. For evaluating the relative contribution of different dissolved gases on the porosity formation during liquid steel solidification, a sequential microsegregation-thermodynamic calculation procedure has been developed and applied for predicting their safe limits in liquid steel. Based on model prediction appropriate countermeasures were recommended for mitigating the problem of wire rod chipping during hot rolling of continuously cast low carbon steel billets.