Research On Liquid Steel Surface Velocity And Nozzle Structure Optimization Of Rectangular Billet Mould

As the competition of steel market, people pay more and more attention to the quality of the steelproducts, so more and more high to the requirement of continuous casting production.Mould as thekey link in continuous casting plays an important role for the quality of billet.A good flow field ofmolten steel in mould can promote slag melting and reduce slag entrapment, which is helpful forinclusion floating and dislodging and ensure the thickness of solidification shell.In this study,a rectangular billet continuous casting with the section of440mm×150mm of a steelcompany in Tangshan as the object of study. In the production process of this section of therectangular billet mold,the free surface is too quiet and upper heating for melting slag is poorer andmolten steel impact depth is larger and high temperature move down and so on. The article studies theinfluence of surface velocity and flow field on the different submerged entry nozzle exit area ratio anddifferent immersion depth and different side opening angle in the process of nozzleoptimization.Optimize a suitable nozzle for the continuous casting and simulate on the characteristicsof the flow field at the time of optimization nozzle position skewing and nozzle clogging.In the experiment, a rectangular billet mold three-dimensional mathematical model is establishedby the simulation software FLUENT and make the free surface flow and the flow field in the mold asevaluation index. System study the influence of nozzle structure parameters and continuous castingprocess parameters change on the flow field by establishing a physical model ratio of1:1similar to theactual producing.The study shows that the original nozzle nozzle exit area ratio and nozzle angle is bigger,optimization of nozzle exit area ratio is2.42and nozzle angle is25°. Reduce the nozzle exit area ratioand nozzle angle can increase the surface velocity and alleviate the generation of liquid surface vortex.When the nozzle position skewing or nozzle clogging occurred would cause the asymmetric flow ofmolten steel in mould. The degrees of nozzle position skewing under different direction on the theflow field are different, but both can cause vortex phenomenon in a liquid surface.Nozzle appearsunilateral clogging will make the quantity of flow different on both side and asymmetric flow inmold.and the increase of clogging degree can increase the degree of asymmetry of the flow field.