| The electromagnetic field is widely used in the modern continuous casting production process.The electromagnetic stirring technology of the crystallizer uses a low-frequency magnetic field to drive molten steel to strengthen its convection movement,improve the heat and mass transfer conditions,and thus improve the quality of continuous casting billets.At the same time,the electromagnetic field exerts a force on mold flux,affecting its physical and chemical properties.However,it is difficult to directly observe the movement and change of the flux in the mold because the environment of the flux in the mold is high temperature and non transparent.Numerical simulation is one of the best methods to study the physical and chemical properties and metallurgical behavior of mold flux under the electromagnetic field.The dielectric constant is an important parameter that affects the accuracy of numerical simulation.At present,there are few reports about the simulation of the influence of electromagnetic field on the properties of mold flux,which also reflects the blank of this research.On the one hand,the understanding and research on the influence of electromagnetic field on the properties of mold are not enough,on the other hand,the lack of relevant electromagnetic parameters of mold flux affects the calculation and analysis,which is exactly what this paper studies on the dielectric properties of the protective slag reason.This subject applied a combination of high-temperature experiments,micro-analysis,and performance testing to research the effect of low-frequency electromagnetic fields on the microstructure and dielectric properties of mold flux.The research results are helpful to grasp the influence of electromagnetic fields on the dielectric properties of mold flux and provide electromagnetic parameters for the corresponding numerical simulation.Under the conditions of this experiment,the following conclusions were mainly obtained.(1)The electromagnetic field had no significant effect on the phase of mold flux after crystallization,but it promoted the crystallization process of mold flux,thereby affecting its dendrite spacing and dendrite width.As the magnetic field strength and frequency increased,both the dendrite spacing and dendrite width decreased,and they have the following relationship with the electromagnetic field parameters:d(?m)=124.33exp(-0.05227f-0.03476B+6.022×10-4Bf)w(?m)=583.64exp(-0.06610f-0.04406B-4.539×10-4Bf)(2)The electromagnetic field affected the dielectric properties of mold flux by affecting its crystallization behavior.Under given alkalinity,when the magnetic field strength and frequency increased in the range of 10 to 30 m T and 4 to 12Hz,respectively,the dielectric constant,quality factor,and temperature coefficient of resonance frequency of mold flux increased accordingly.When the magnetic field intensity was 30 m T,and the frequency was 12Hz,the three dielectric parameters reached their maximums.(3)Under given magnetic field strength and frequency,when the basicity of mold flux increased in the range of 0.9 to 1.1,its dielectric constant,quality factor,and temperature coefficient of resonance frequency increased,and the maximums are 7.25,21200 GHz,and-27.1 ppm/?,respectively. |
PDF Full Text Request