Numerical Simulation Of The Blockage Of The Continuous Casting Tundish

High melting point solid inclusions tended to deposited on the nozzle wall in continuous casting,causing the nozzle nodulation,even closed the nozzle,and it was a serious problem for the quality of casting billet and the efficiency of the furnace even poured more.In view of the problem of tundish nozzle clogging,research of preventing measures were carried out,and the certain effect had been obtained,but problem of nozzle clogging still had not been solved thoroughly.It was found that high content of acid soluble steel was easy to clogging in the production site of a iron and steel company,it was generally to clogging the two side holes,and if there is no change for nozzle in time,then it will clogging the hole of nozzle.Replace the nozzle side hole usually clogged off a third of the aperture,Al₂O₃ was the main nozzle blockage.Aiming at the real congestion of the iron and steel company,the thesis makes research on the nozzle of slab continuous casting tundish.The numerical simulation methods are currently being used to obtain and analyze the steel flow and inclusion deposition of tundish nozzle.Simulated the inclusion deposition in different particle size,particle concentration and different plug nozzle under the condition of clogging.Then changed the drawing speed and argon gas flow rate,analyzed the the effect of different process conditions on the inclusion deposition,so as to provide theoretical guidance for field control nozzle clogging.The main conclusions of this study are as follows:?1?Larger adhesion force was existent after the Al₂O₃ inclusion passed to the nozzle wall and contacted each other,and it is greater than the stripping force,not from in the condition of steel flowing.It would occur solid-phase sintering in the condition of high temperature of molten steel,then formed a relatively stable Al₂O₃ cluster.So Al₂O₃ inclusion once passed to the nozzle wall contact each other,then easy adhere to the wall,and caused nozzle clogging.?2?Inclusion deposition mainly occurred in the area of molten steel impact,cyclotron and flow separation.In the bottom of the nozzle and the export,inclusion particles are more likely to pass to the nozzle wall,at the bottom and exports of the nozzle easyly to clogging up.And it was easily to deposit with greater concentration of inclusion particles.?3?Molten steel and refractory material initial layer formed by blocking reaction,though far short of jams thickness,but will increase surface roughness,and as the attached base,promoting the floating inclusion particles in molten steel and the adhesion of congestion.If appear at the bottom of the nozzle and exit clogging,will further promote the inclusion particles to the nozzle wall of transfer and deposition,aggravate congestion.?4?In the case of other conditions remain unchanged,drawing speed increase promotesinclusion particles deposition on the nozzle wall.?5?Argon injection could improve the pressure inside the nozzle,and the pressure was larger with the greater argon gas flow rate;but only when the stopper argon blowing argon gas flow is less than 10 L/min,tundish nozzle and submerged nozzle joint stress is still lower than atmospheric pressure value.?6?Little argon gas flow rate could reduce the deposition rate,when the argon gas flow increases to 10¹5 L/min,the deposition rate increased instead,although with argon gas flow continues to increase,the deposition rate began to decrease,but too much the argon gas flow of crystallizer liquid surface,the liquid steel flow state and adverse impact on quality of casting billet.Therefore,the liquid steel flow,be taken into account in the process of production mold surface condition and prevent the inclusion of sedimentary conditions change to fine-tune the argon gas flow reasonably.