Research On The Effect Of Mold Electromagnetic Strring And Nozzle Structure On The Solidification Process Of Continuous Casting

With the extensive application of M-EMS(mold electromagnetic stirring)technology and the improvement of nozzle shape,many metallurgists have done a lot of research on the flow and temperature changed in the mold.However,little research has been done on the flow and solidification of molten steel in the second cold zone with E-MES and different SEN(submerged entry nozzle)structure.Therefore,it is important to optimize the process of continuous casting and obtained the excellent billet quality by systematically studying the effects of E-EMS and SEN shape on the magnetic field,flow field and temperature field during the solidification process.This paper took the GCr15 steel with a diameter of 250 mm as the research object.The solidification process of the liquid in the secondary cooling zone was the main content,and the solidification mechanism,heat transfer and flow equation and Maxwell equation group were the theoretical basis.The electromagnetic field,flow field and temperature field were coupled by numerical simulation.The numerical simulation of the solidification process of the round billet during the secondary cooling zone under the M-EMS and different SEN structure was carried out.The effects of different current intensity of electromagnetic stirring and SEN structure on the temperature field and flow field distribution of the round billet were analyzed.According to the thickness of the shell and the fluctuation of the meniscus,the reasonable current intensity and the shape of the SEN were determined.The results showed that electromagnetic force could change the flow pattern of molten steel in the mold,so that the heat transfer rate of the molten steel in the mold was accelerated,the position of the hot zone was improved,the solidification rate of the outlet was increased.As the current intensity increases,the temperature of the round billet in the secondary cooling zone decreases and the thickness of the shell increases.Compared with the straight SEN,the porous SEN could enhance the vortex flow in the mold,the vortex was moved up,the temperature of the meniscus was improved,and the internal molten steel was accelerated to the wall.Therefore,the surface temperature of round billet was higher,its center temperature was lower,and the solidification rate of second cold zone export was larger.The effect of the porous SEN on the flow field and temperature field of the round billet was similar to that of the electromagnetic stirring.With electromagnetic force joined to the porous SEN model,the temperature of the molten steel in the mold increased and no solidified shell was formed.By analyzing the numerical simulation results,the stirring current intensity of round billet continuous casting mold is selected as 500 A and the electromagnetic stirring should not be added to the porous SEN or applied a smaller intensity of electromagnetic force.