An Analysis of Fluid Flow and Mixing Phenomena in Liquid Pool of a Continuous Casting

Abstract

In order to make clear the fluid flow and mixing phenomena of the liquid pool in a continuous casting process, experimental studies were done by casting successively two melts which were different in the composition. The fluid flow and the mixing intensity of the molten steel were obtained based on the measured values of concentration changes at the jointed part of the two heats. Furthermore, the solidification rate of the molten steel was calculated considering the mixing effect on the heat transfer.
The results obtained are as follows.
(1) Molten steel in the mould region is observed to be perfectly mixed.
(2) It can be considered that the curvature of the continuous casting machine has no effect on the mixing phenomena of molten steel.
(3) The mixing phenomena of molten steel can be well simulated by the diffusion model which is known to be often satisfactory for the evaluation of the dispersion in mixing experiments on the assumption that the process takes place by eddy diffusion. The distribution of the back mixing coefficient in liquid pool is evaluated based on this model.
(4) The effect of the pouring temperature on the thickness of mushy zone is calculated considering the mixing effect of molten steel on heat transfer. The relation between the pouring temperature and the solidified structure of a cast slab is discussed.
(5) A good agreement is found between the calculated solidification rate of solidus line and the experimental one. It is found, however, that there is a significant difference between the calculated and experimental solidification rates of the liquidus line. The reason of this difference is discussed.