Numerical Study on the Capture of Large Inclusion in Slab Continuous Casting with the Effect of In-mold Electromagnetic Stirring

Abstract

Large inclusions captured by the solidifying shell deteriorate the surface quality of interstitial free steel. To investigate the capture of large inclusion in slab continuous casting, a three-dimensional model coupling flow field, solidification and inclusion motion has been developed. Additionally, to study the effect of in-mold electromagnetic stirring (M-EMS) on large inclusion capture, the electromagnetic field has been also coupled in the model. The results of electromagnetic field indicates its centrally symmetrical distribution on the cross-section, and the electromagnetic force swirls on the cross-section. The effects of M-EMS on flow pattern, solidification and inclusion capture have been discussed. The M-EMS significantly changes the flow pattern and solidifying shell thickness. The inhomogeneous distribution of large inclusions existing in the slab surface in the slab surface are different between the cases with and without M-EMS. Furthermore, the number of captured inclusions increases at 0-0.02 m beneath the wide surface and decreases at 0.02-0.04 m beneath the wide surface in response to the application of M-EMS. Large inclusions in steel were quantitatively analyzed by the galvanostatic electrolysis method. The experimental results are in agreement with the simulation results, suggesting that the model is valid.

Numerical Simulation on Multiple Physical Fields Behaviors in Billet Continuous Casting with Different Stirrer Positions

“…[13,21,22] Continuity equation The common standard k À ε turbulence model is applied to calculate the effective turbulent viscosity μ eff during the continuous casting process with M-EMS.…”

Assessment of the efficiency of non-metallic inclusions removal through the use of centrifugal force at different stages of steel production

“…До першої групи запропоновано віднести методи, що передбачають зміну картини циркуляційних потоків у ковші таким чином, щоб прискорити спливання НВ у шлакову фазу або їх вловлювання спеціальними керамічними фільтрами. До "Сучасні проблеми металургії", № 23 -2020 ISSN-print 1991-7848 103 ISSN-online 2707-9457 цієї групи належать продувка інертним газом [1][2][3][4], електромагнітне перемішування [1,[4][5][6][7][8][9], фільтрація [1] й установка в промковші перегородок і порогів [1,10]. Методи другої групи, на відміну від першої, передбачають вплив на хімічний і фазовий склад, а також агрегатний стан включень.…”

“…На думку авторів, значної уваги у цьому напрямку заслуговують методи центрифугування, реалізація яких у процесах позапічної обробки й безперервного розливання можлива за допомогою електромагнітного перемішування й за рахунок тангенціального підведення металу в ротаційну камеру. Обертовий рух металу методом індукційного перемішування реалізовується в сталерозливних ковшах (ASEA-SKF) [4], промковшах (CF-Tundіsh) [1] і кристаллизаторах (MEMS) [5][6][7][8][9]. За рахунок тангенціального спрямовування потоку можливо створювати вихровий рух металу у проміжному ковші [14] та кристалізаторах [15,16].…”

Electromagnetic Forces in Continuous Casting of Steel Slabs

“…The strength and direction of the force depends on the magnet orientation, the applied current, and the effective frequency of the phase shift. Three types of horizontally-moving magnetic fields near the nozzle ports are EMLA [16,32,33,40,51,56,121], EMLS [16,32,33,40,51,56,122], and EMRS [16,32,33,40,51] or M-EMS [123,124]. Alternatively, EMC applies vertically-moving magnetic fields near the meniscus [36][37][38].…”

“…Thirdly, EMRS or M-EMS can rotate the flow around the perimeter of the mold, which is expected to wash particles away from the dendritic solidification front, in order to lessen particle entrapment, especially near the meniscus region [123,124]. In addition, the mixing effect of the rotating surface flow is designed to make the temperature distribution in the liquid near the mold top surface and meniscus region more uniform, especially in the central region of the mold near the nozzle, lessening the associated problems of meniscus freezing and lowering hook depth [123,124]. This is an alternative way to previously discussed methods to increase surface flows, with the potential benefit of less detrimental level fluctuations, if great care is taken.…”