Numerical Simulation On EMS In Continuous Casting Mold Of Billets And Its Application At ChongSteel

Electromagntic stirring which is one of the effective methods for controlling solidification of metal, has a large-scale application and profound industrial base. The mechanism that M-EMS improves solidifying structure and strands quality is intensive fluid rotating movement by means of electromagntic induction which transforms electromagntic power into electromagnetic force that impel the liquid metal to stir revolvably.M-EMS technology has been carried out on No.1 and No.5 billets caster in Chongsteel. But with the increase of steel brands and casting speed, further study must be done to make sure the better matching between M-EMS process parameter and billet quality. This study will present a theory and practice foundation to help M-EMS be applied properly at Chongsteel.In order to explore magnetic flux distribution with M-EMS and computation in theory of stirring frequency, magnetic field in the molds scaled 150mm×150mm and 150mm×210mm billets were measured and analyzed. The results indicated that the dimensional magnetic flux distribution was related to M-EMS current and frequency as well as the cross section of the mold with the same material and wall thickness, the same stirrer and its installed location.The values of magnetic flux reached its maximum in the middle plane of stirrer and became samller towards the end plane of mold . Magnetic flux density of center and wall at the top and bottom of mold are almost equal to each other. But the difference between them increased gradually from center to edge at the mold horizontal section. And this kind of difference largened with current increased.The optimal frequency for 150mm×150mm and 150mm×210mm casting billet are both 4Hz.The results were very helpful to research the distribution of the magnetic field, Electromagnetic stirring force, rotation of liquid steel, and design of M-EMS process parameter.Based on Maxwell electromagnetic theory, the fluid field with M-EMS for billets was studied by means of numerical simulation combined with experiment. This passage gained analytic electromagnetic force by Maxwell equations and describes the velocity field by Novier-Stokes equations. FLUENT is applied to obtain the velocity field controlled by electromagnetic force.The industrial experiments on the effects of M-EMS on the quality billets were carried out. Grade of the different steel grades billets on central segregation,central shrinkage and central porosity were evaluated with diversed EMS parameters. Inclusions of samples including the type, form, quantity, size and distribution of them were observed with microscope and the composition of them were confirmed with EDS The optimal EMS parameters were obtained by synthetically comparing the relation between EMS intensity and strands quality.