| Electromagnetic braking technology is a mature metallurgical technology,it’s widely used in continuous casting production process.It can reduce the disturbtion of slag,stabilize the liquid level fluctuation,promote the separation of non-metallic inclusions floating and prevent leakage in Continuous casting process.Common electromagnetic brake technology sush as Regional-type electromagnetic brake,The level magnetic field of electromagnetic brake and Flow Control Mold have their own advantages and disadvantages.Thin slab continuous casting is a near-final molding and continuous casting process,Thin slab continuous casting has short process,short production cycle,low energy consumption,finished product rate,good internal quality of the thin slab,however,the flow regime inside the thin slab hopper crystallizer is difficult to control.In this paper,based on the existing electromagnetic automation technology and thin slab casting technology we put forward new Braking technology called VC-EMBr to effectively control the flow of molten steel in the mold and improve the quality of continuous casting slab.The article first uses the ANSYS software to establish the magnetic field calculation three-dimensional model to simulate distribution of VC-EMBR’sthree-dimensional magnetic field.Then,the three-dimensional mathematical model of molten steel flow in slab continuous casting mold is established by FLUENT softwave..then loading the magnetic flux density solved by ANSYS for coupling the calculation of magnetic field and fluid field By means of calling MHD module.In this paper,the numerical simulation of the magnetic field and flow field is simulated under VC-EMBr,the main conclusions of the numerical simulation of three-dimensional magnetic field of the VC-EMBr echnologies are as follows:(1)After the VC-EMBr is applied,the magnetic field area is concave,the magnetic induction intensity is larger in the core area,and the space area around the core is smaller.The magnetic flux density distribution in the main magnetic pole coverage area and the secondary magnetic pole coverage area is relatively uniform,The magnetic field generated by the primary and secondary magnetic poles covers the height range from the free surface to the impact point of the jet,the magnetic field covers the critical area where the liquid flows.(2)Current intensity and the magnetic induction generated by a linear relationship.With the increase of electromagnetic braking current intensity from 550A to 1100A,the magnetic induction intensity of the magnetic pole coverage increases with the increase of the magnetic induction intensity from 0.2T to 0.4T.(3)The liquid steel without VC-EMBr flowing out of the submerged water outlet forms a slightly downward-sloping mainstream and changes direction after forming the narrow edge of the mold directly on the slab Up and down the formation of the upper backflow zone and the lower backflow zone,the upper and lower backflow zone flow conditions will deteriorate the slab quality.(4)For the conventional continuous casting of thin slabs,the velocity and turbulent kinetic energy of the free surface and narrow face of the molten steel increase with the increase of the billet speed.With the increase of the billet speed,the impact strength of molten steel on the narrow face of the mold is enhanced.(5)For the continuous casting of thin slabs,deeper penetration of the nozzle increases the velocity and turbulent kinetic energy of the free surface.However,the immersion depth is not conducive to the flow and heat transfer in the upper recirculation zone,which is not conducive to the melting of the flux and the crystallization Heat transfer between wall and blank shell.Moreover,with the increase of the immersion depth of the nozzle,the impact on the narrow face of the mainstream also directly increases,which is not conducive to the formation of the primary shell,aggravating the erosion of the narrow face,the increase of the immersion increase depth of the nozzleand the depth of penetration increases the impact depth,It’s not conducive to the floating slag floating bubble separation.(6)Under the action of vertical combined electromagnetic brake(VC-EMBr),the flow state inside the mold is obviously improved.The flow velocity,the turbulent kinetic energy at the freeface,the vertical velocity and turbulent kinetic energy of the narrow face decrease after applying the VC-EMBr and,which will help to inhibit the effect of eliminating the casting speed to increase the harm caused by continuous casting.(7)Under the action of vertical VC-EMBr,the VC-EMBr will also produce a steady suppression effect on the molten steel flow in the mold when the pulling speed is increased,The application of VC-EMBr can ensure the quality of billet at high drawing speed and meet the requirements of high output and high quality of billet in modern industrial continuous casting.(8)Under the action of VC-EMBr,the higher the magnetic induction intensity is applied,the stronger the suppression ability of the vertical combined electromagnetic brake to the molten steel is,the overall flow velocity,the turbulent kinetic energy of the narrow and are reduced,which is conducive to flow control within the mold,VC-EMBr can play a stable meniscus fluctuations,reduce the risk of entrapment,to avoid the role of breakout. |
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