Numerical Simulation Of Flow And Heat Transfer Of Continuous Casting Applied Liquid Protective Slag

As an indispensable material in the continuous casting process,slag is widely used in the production of pre-melted solid slag.However,in the production of high-alumina steel,the aluminum in the molten steel will react with the Si O₂in the slag to form Al₂O₃,which will cause the deterioration of the slag viscosity and crystallization,resulting in defects such as dents and cracks in the billet.At the same time,the corrosion of chemical element F in the flux is easy to cause harm to the environment and human body.Therefore,one of the ways to solve the above problems is to use additional liquid protective slag.However,the influence of external liquid slag on the process parameters of continuous casting has not been studied theoretically.In view of the above problems,this paper aims to study the flow and heat transfer behavior of liquid slag under different process parameters,which can be used as a theoretical reference in actual production.The main conclusions of the paper are as follows:（1）The liquid slag forms a reverse circulation under the action of the molten steel.The center of the circulation is located in the central cross section of the liquid slag layer,and the impact position of the molten steel at the steel slag interface is located near 100mm from the narrow surface of the mold.（2）When the casting speed increases,the velocity increment of liquid slag at the center surface of ideal liquid slag increases by 125.5%,and the temperature increment at the steel slag interface is the largest,and the maximum temperature increases by 19.87K.（3）With the increase of nozzle submergence depth,the velocity of liquid protective slag near the upper surface of liquid slag decreases most obviously,the maximum velocity is 33.3%,and the temperature near the upper surface of liquid slag decreases most obviously,the maximum temperature decreases by 26.81K.（4）When the port angle increases from 12°to 15°,the maximum velocity decreases slightly and the maximum temperature increases slightly.When the port angle is 18°,the temperature and velocity are the lowest.（5）As the thickness of liquid slag layer increases from 35mm to 55mm,the maximum temperature of liquid protective slag decreases most obviously on the near upper surface of liquid slag,which decreases by 76.87K;The flow rate of45mm thick liquid slag layer is about 20%higher than that of the other two.When the liquid slag layer is 45mm,the fluidity and heat preservation of liquid slag are the best.（6）When the slag thickness is 15mm and the inclination angle of the nozzle is20°,the maximum drawing speed that can be tolerated is 1.1m/min without the molten steel being exposed.When the inclination angle of the nozzle is 25°,with the increase of the drawing speed,the maximum speed of the three surfaces increases from 0.038m/s,0.028m/s,0.043m/s to 0.059 m/s,0.035m/s,0.057m/s;when the drawing speed is 1.4m/min,the liquid slag layer fluctuates greatly due to the impact angle of the molten steel,which easily affects the solidification of the shell.When the inclination angle of the nozzle is 28°,with the increase of the drawing speed,the maximum speed of the three surfaces increases from 0.041m/s,0.023m/s,0.027m/s to 0.083 m/s,0.047m/s,0.064m/s;when the drawing speed is 1.0m/min,the large circulation inside the liquid slag layer is already very weak.（7）Under the conventional continuous casting process,the casting speed is1.2m/min,the immersion depth is 140mm,the preferred slag layer thickness and the port angle are 45mm and 15°,respectively;The thickness of slag layer is 15mm,and the applicable drawing speed is 1.0m/min-1.2m/min when the port angle is 25°,and1.2m/min-1.4m/min when the port angle is 28°.