Simulation of low carbon steel solidification and mold flux crystallization in continuous casting using a multi-mold simulator

An inverted water-cooled multi-mold continuous casting simulator was used to investigate initial solidification of low-carbon steels and crystallization of mold flux. Embedded mold thermocouples showed characteristic temperature profiles dependent on parameters including casting speed, oscillation frequency, and stroke. Higher maximum temperatures for thermocouples at higher casting speeds, higher frequencies, and lower stroke lengths were observed. The surface of the as-cast steel strips showed oscillation marks similar to those of industrially cast slabs and higher casting speeds resulted in shallower oscillation marks. The measured pitch agreed well with the theoretical pitch suggesting the multi-mold simulator to be a cost-effective alternative to pursue fundamental studies on initial solidification in the mold. Analysis of the mold flux taken between the copper mold and solidified steel shell showed highly dendritic uni-directional crystallization occurring within the flux film suggesting that the heat transfer direction is dominantly horizontal towards the water-cooled copper mold. In addition, the solidified flux located at the upper to lower part of the mold suggested morphological differences in the size and shape of the crystalline phases indicating that crystallization ratio can increase depending upon the retention in the mold and subsequently decrease radiative heat transfer as the flux traverses down the mold.