Simul Ation Of Inclusion Motion Incontinuous Casting Mold Underelectromagnetic Oscillation

The presence of inclusions in steel can easily lead to the extension of fatigue crack of steel,resulting in material fracture and catastrophic equipment accident and personal accident.At present,researchers mainly remove inclusions in continuous casting mold by optimizing structural parameters,electromagnetic stirring,electromagnetic braking and other methods.Therefore,this paper systematically studies the influence of electromagnetic oscillation on the movement of inclusions in the continuous casting mold,which is of great significance for optimizing the electromagnetic oscillation parameters.The main research contents are as follows:Firstly,the motion of inclusions in a thin slab continuous casting mold was simulated numerically,and the motion of inclusions in the mold was obtained by Lagrange method.Through the establishment of water simulation experiment device for physical simulation,Proanalyst software was used to analyze the movement diagram of inclusions taken by the high-speed microscopic camera,and the movement of inclusions in the mold was obtained.By comparing the physical simulation results with the numerical simulation results,the movement rules of the inclusions in the crystallizer were obtained.The results show that the movement path of inclusions can be divided into three types:some inclusions flow into the lower reflux region and hover in the lower reflux region;Part of the flow into the upper reflux zone,hovering in the upper reflux zone;Some of them flow directly from the outlet of the crystallizer.When the drawing speed is 0.01m/s and the depth of nozzle immersion is 100 mm,the inclusion can be effectively removed by floating up.The higher the pull speed,the easier it is for the inclusions to hover in the lower reflux zone,thus making it easier for the inclusions to flow away from the mold outlet.The deeper the depth of nozzle immersion,the lower the center of inclusion hovering in the upper and lower reflux zone,and the easier it is for inclusion to flow away from the mold outlet.The velocity of the inclusions reaches its maximum when immersed in the nozzle and flows out.With the increase of the time of movement in the crystallizer,the velocity decreases gradually.With the increase of drawing speed,inclusion movement speed increase,change range of speedincrease,inclusion hovering in the crystallizer movement cycle shorter,led to inclusion of movement in the crystallizer time reduced,not only bad for inclusion removal,and easy to make the inclusions from mold exports,causing permanent defects of slab.The quantity distribution of inclusions is divided into three parts: one part hovers in the upper and lower reflux zones,one part floats up to the free liquid level,and the other part flows away from the mold outlet.When the drawing speed is 0.01m/s and the depth of nozzle immersion is 100 mm,the inclusion particles are mostly distributed in the upper reflux area,and the number of particles floating to the free liquid surface is large,which is conducive to the removal of the inclusion.With the increase of drawing speed and immersion depth,the inclusions are mostly concentrated in the lower reflux zone,and the amount of the inclusions flowing away from the outlet of the crystallizer increases,which affects the quality of the molten steel.Secondly,the mathematical model of crystallizer under the action of oscillating electromagnetic field is established,the influence of electromagnetic oscillation on the movement of inclusions is studied by means of numerical simulation,and the influence rule of electromagnetic oscillation on the movement of inclusions is obtained.The experimental results show that after the application of oscillating electromagnetic field,the time of the inclusions in the crystallizer is increased,and the probability of the inclusions floating up is increased,which is beneficial to the removal of the inclusions floating up.When the electromagnetic force is 1.2×10-4N/m3,the oscillation and hovering motion period of the inclusions in the mold,the movement path of the inclusions and the movement time of the inclusions in the mold are relatively long,which is conducive to the floating removal of the inclusions.With the decrease of electromagnetic force,the movement path of inclusions and the period of hovering oscillation become shorter,which is easy to make inclusions flow away from the exit of crystallizer and affect the quality of molten steel.When the electromagnetic frequency is 200 Hz,the inclusions have a longer oscillation circle motion period and motion path in the mold,and a longer oscillation motion time in the mold.With the decrease of electromagnetic frequency,the movement track and period of the inclusions in the crystallizer become shorter,so that the outflow rate of the inclusions increases and the cleanliness of the molten steel is affected.In conclusion,electromagnetic oscillations change the trajectory of inclusions in the crystallizer,and the appropriate electromagnetic force and frequency make the inclusions oscillate and hover in the crystallizer for longer periods of time,path and time.It was found that the longer the inclusions hovered in the crystallizer,the more favorable it was to remove the inclusions and distribute them evenly.