Tundish Flux for Making Al killed Steel in Continuous Casting

摘要

PURPOSE: A tundish flux for manufacturing Al killed steel in continuous casting is provided which is injected into tundish and melted therein during continuous casting of Al killed steel to secure cleanliness of molten steel by fusing and absorbing inclusions separation floated inside the tundish. CONSTITUTION: The tundish flux for manufacturing Al killed steel in continuous casting comprises 50 to 60 wt.% of CaO, 30 to 40 wt.% of Al2O3, 5 wt.% or less of SiO2, 1 to 5 wt.% of MgO and a balance of impurities, wherein a ratio of CaO/Al2O3 is in the range of 1.4 to 1.8, the SiO2 is in the range of 3 to 5 wt.%, cleanliness of molten steel can not be expected due to deficiency of Al2O3 absorption power if less than 50 wt.% of CaO is contained in the flux while slagging is difficult as melting temperature of the tundish flux is increased if 60 wt.% or more of CaO is contained in the flux, workability is worsened due to wear of tundish dam, weir and shroud nozzle in case of less than 30 wt.% of Al2O3 while cleanliness of molten steel can not be obtained as there is no absorption power of Al2O3 inclusions in case of 40 wt.% or more of Al2O3, it is necessary to maintain at least 3 wt.% or more of SiO2 since the flux is solidified if content of SiO2 contained in the flux is too less even though SiO2 content in the flux is preferably required to be controlled to 5 wt.% or less, MgO is added to the flux to prevent deterioration of wear of a coating layer of the tundish made of MgO, and it is preferable not to exceed 5 wt.% of MgO in the flux since a mass of the non-melting state can be formed due to ascent of melting temperature in case that MgO content in the flux is excessive.