Research on the control of large particle inclusions on 475 mm extra-thick slab surface by mold electromagnetic stirring
Extra-thick slab has become an important iron and steel material for infrastructure construction and is widely used in military and civilian applications.The large particle inclusion on the surface of a billet is one of the key factors affecting the quality of the billet.To investigate the influence of mould electromagnetic stirring(M-EMS)on the surface inclusions of 475 mm extra-thick slab continuous casting,a comparative test with and without EMS was conducted.The large particle inclusions in the samples were extracted by an hydrous large-scale electrolysis method,and the quantity density and mass density were calculated.The results show that the inclusions of each size on the surface of the billet with EMS can be reduced obviously compared with that without M-EMS,among which the largest-particle inclusions with the size greater than 150 μm have the largest reduction,and the mass density is reduced from 3.817 mg/kg to 1.511 mg/kg.The results also indicate that the use of mould electromagnetic stirring can effectively reduce the large particle inclusions on the surface of extra-thick slab;at the same time,the inclusions are found to be deoxidized products produced in the production process(Al2O3-SiO2 or pure Al2O3),protective slag involved in the casting process(contains Na2O)and refractories that fall into the liquid steel as the molten steel washes away.The components are silicates such as CaO-MgO-Al2O3-SiO2 and calcium aluminate.
extra-thick slabelectromagnetic stirring of moldanhydrous large-scale electrolysisinclusion
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