Coupled Simulation On Field Flow And Temperature Field In The Beam Blank Mould

The fluid flow and free surface fluctuation of the liquid steel in the mould have a direct effect on the initial solidification progress, which will influence the sequence of casting and quality of producting accordingly. The flow behavior of the liquid steel is mainly dependent on the casting conditions, such as the product crosssection, casting speed, SEN type and the geometry of the nozzles.For beam blank casting process, a multi-phase fluid flow model is adopted for the description of the effect of casting speed, the immersion depth of a straight-pored nozzle and the outlet angle of the three quarto-furcated nozzle on the fluid flow and free surface fluctuation. It is demonstrated that firstly, when using the straight-pored nozzle with the increase of casting speed, the location of the vortex will move downwards and the jet depth of the liquid steel in the mould will increase 60mm with an increased casting speed by 0.2m/min; at the same time, velocity and waveness of the liquid at free surface will be increased; With the increase of the immersion depth, the jet depth will be larger while the location of the vortex will be lowered and the waveness and liquid velocity at surface will be decreased accordingly. Secondly, the lateral opening nozzle with the enlargement of the outlet angle, the impringing spots will move up, velocity of the liquid steel at free surface and the location of the waveness will be increased; however, when the outlet rake angle increased to 15 degree, the waveness error will be 5.3mm at the direction of frange effective width, and it will be 6.9mm at the direction of web plate in the mould, so the outlet angle should not be over 9 degree for the purpose of avoiding happening of mold powder entrapment.The effect of structure of the submerged entry nozzle on the shell thickness out of the mould has been researched based on a coupled fluid flow and heat transfer model. When applying the straight-pored nozzle, because of the distance between nozzle and the center of narrow face and the corner of R is not too big, the shell is scoured badly by the liquid steel longitudinal 450~550mm direction of the mould, so it will remelt and become thin; when using the lateral opening nozzle, on the top of the mould, especially above 200mm, the shell thickness at the center of web plate and the corner of frange effective width do not form commendably, on account of scouring of the liquid steel and it will form gradually at the height of 300mm. Shell thickness will increase with the increase of height of the mould and it will be symmetrical at the outlet of the mould.