Optimization Of Nozzle Configuration Parameters For Heavy Slab Mold By Numerical And Physical Simulation Method

With the rapid development of the continuous casting technology and our higherrequest for slab quality, the metallurgical effects of mold and submerged entry nozzle(SEN) become more and more important. The flow of liquid steel behavior plays adecisive role for slab quality, and it directly affects mold heat transfer and inclusionfloatation. The unreasonable flow will seriously affect the quality of continuous castingblank and smooth operation, besides the casting speed and gas blowing rate like theseprocess parameters, the liquid steel flow behaviors is mainly affected by the structureparameters of SEN. Therefore, it’s very important to research and optimize the structureparameters of SEN to improve slab quality and ensure continuous casting operationsmooth.Taking the slab mold at NO.3continuous caster of the steel company as theresearch object. The influence of the submerged entry nozzle (SEN) structuralparameters (the bottom structure of SEN, side hole angle, exit area ratio and side holeshape of SEN) on the flow field in the mould by means of physical simulation andnumerical simulation, Base on these research to optimize current SEN, and alsoproposed the evaluation standard of wide slab caster mold fluid flow.The different section of submerged entry nozzle was optimized based on physicalsimulation and numerical simulation. The results show that use the former SEN, levelfluctuation in mold is dead cause of upper cycle flow was weak, it is easy to find theslag-bonding on the mold of meniscus and edge, this will reduce the flow rate of moldfiux into the gap between billet and copper mold, at the same time the friction in themold will increased rapidly. As to more wider section even appear the situation thatstream can’t reach the narrow wall. Against these problems for the former SEN,designed a serious of new nozzles by changed of the submerged entry nozzle (SEN)structural parameters. Elected three SENs which are the most suitable to the existingconditions by the simulation. SEN(flat bottom, side hole angle-15°, exit area ratio2.21, the side of the hole aspect ratio1.42) to be the section of250mm×(2000,2200)mm optimize SEN, SEN(flat bottom, side hole angle-15°, exitarea ratio1.81, the side of the hole aspect ratio1.42) to be the section of250mm×2500mm optimize SEN, SEN(flat bottom, side hole angle-12°, exit area ratio1.59, the side of the hole aspect ratio1.25) to be the section of 300mm×(2000,2200,2500)mm optimize SEN. The rang of immersion depth of SENcontrol in140mm-160mm. The range of casting speed in0.8m min-1.3m min. Theoptimized SEN effectively enhanced the circulation flow strength, got a morereasonable flow field, improved the quality of casting slab on the premise of no slagentrainment in the mold.