Study On The Fluctuation And Entrapment Behaviors Of Molten Slag In The Continous Casting Mold

The mold design and operation are very important for improving the quality of slab in continuous casting process. In order to achieve the metallurgical function of a mold, the suitable flow behavior of steel liquid in a mold must be kept and the slag entrapment must be avoided. Therefore, it is important for improving the equality of the surface equality and then improving the equality of steel to study and control the flow field and level fluctuation in the mold.The prototype of the mold comes from the slab mold (cross section size is 1128mm×242mm) of the Shougang Jingtang company in China, and the study is focused on the fluctuation and entrapment behaviors of molten slag through physical and numerical simulation in the continuous casting mold. Operating parameters and geometry dimension of SEN were investigated by means of orthogonal experiment. Furthermore, the effect of casting speed, immersion depth and port angle on the impact depth, level fluctuation and entrapment of slag is dicussed systematically. In addition, a VOF model combining k-ε turbulence model is developed for molten steel flow and level fluctuation in the mold, and then the effect of immersion depth of the submerged entry nozzle (SEN) on the level fluctuation behavior of the molten steel in the mold was analysed based numerical method.The following conclusions can be obtained through the present study:(1) In term of the impact depth, the immersion depth is the most important factor, and port angle are the more important factor than casting speed. And in term of the level fluctuation of slag, the casting speed is the most important factor, and port angle are the more important factor than immersion depth under the present experimental conditions,(2) Experiment studies the quantitative relationship and the law between the casting speed, immersion depth, port angle and impact depth, level fluctuation. It turned out that the surface fluctuation is intensified and the impact depth becomes shallow with increase of casting speed; the surface fluctuation becomes shallow and the impact depth is intensified with increase of immersion depth; the the surface fluctuation becomes shallow and the impact depth is intensified with increase of port downward angle.(3) Simulation results show that the fluctuation of free surface is unsteady. The fluctuation is more serious at meniscus by compared with outlets of SEN and the fluid velocity at free surface decreases with increasing immersion depth, thus the fluctuation of free surface is weakened. Consequently, the entrapped behavior of the slag can be alleviated. The similar phenomena are also observed in the experiments. Furthermore, the relationship between velocity and turbulence kinetic energy at the level fluctuation of the free surface is obtained.