In order to increase the beam blank cleanliness, the aim of this work is to analyse the flow field in the mould of beam blank continuous casting, to find the factors influencing the strand cleanliness and then to optimise the process parameters. A three-dimensional steady finite element model was developed to simulate and analyse the turbulent flow field in the mould. The volume of fluid model was used to track the free surface evolution at the meniscus. The influences of processing parameters, such as casting speed and nozzle parameters, on the molten steel flow in the strand (such as vortex location, liquid steel impact depth, velocity and fluctuation of the liquid steel at free surface) were analysed and the optimum processing parameters determined based on mass calculation. The results of this research project have been applied in actual production, and it has been shown that they are very useful and efficient for improving the steel cleanliness and controlling the surface cracks on the beam blank web.

The aim of this work was to analyse the influence of the nozzle structure and parameters on the molten steel flow in beam blank continuous casting. A three-dimensional steady state finite element model was developed to compute the flow field and the meniscus fluctuation in the mould. The volume of fluid model was used to track the free surface evolution at the meniscus. It can be concluded that compared with a through conduit submerged entry nozzle (SEN), a three lateral hole SEN will reduce the impact depth, change greatly the velocity at the free surface and intensify the fluctuation of the free surface. As a whole, the fluid flow in the mould will be improved, which will help to melt the mould powder and improve the absorption of non-metallic inclusions, thus improving steel cleanness. The most rational rake angle for the three lateral hole SEN is 9u. Meanwhile, the SEN immersion depth should be in the range 200-250 mm if the casting speed is about 0?9-1?1 m min 21 .