Abstract: The invention provides a fluoride-free continuous casting mold flux for low-carbon steel, comprising, based on weight, Na2O 5-10%, MgO 3-10%, MnO 3-10%, B2O3 3-10%, Al2O3?6%, Li2O<3%, C 1-3%, and the balance of CaO and SiO2 as well as inevitable impurities, wherein the ratio of CaO/SiO2 is 0.8˜1.3. The mold flux has a melting point of 95˜1150° C., a viscosity at 1300° C. of 0.1-0.3 Pa·s, and a crystallization rate of 10-50% as determined according to the method described in the specification for examining crystallization property. The boron-containing, fluoride-free flux developed according to the invention has a moderate crystallization rate, can be used in a crystallizer to control transfer of heat from molten steel effectively, and has been applied successfully in a low-carbon steel slab conticaster with a metallurgical effect that arrives at the level of a traditional fluoride-containing flux to full extent.

Abstract: A fluoride-free continuous casting mold flux for ultralow carbon steel, comprising the following components in weight percentage: 3-10% of Na2O, 0-3% of Li2O, 3-8% of MgO, 5-15% of MnO, 0-8% of BaO, 4-12% of Al2O3, and impurities with a content of no more than 2%, the balance being CaO and SiO2, wherein the ratio of CaO/SiO2 is 0.8-1.3; the raw materials are mixed and then pre-melted; the pre-melted mold flux requires micro-adjusting according to the component deviation, and the ratio of the pre-melted material is not lower than 70%; then a carbonaceous material of 1-3% by the total weight of the mold flux is added and mixed so as to obtain the finished product mold flux. Said mold flux has a melting point of 1100-1200° C. and a viscosity of 0.2-0.6 Pa·s at 1300° C.

Abstract: A fluoride-free continuous casting mold flux for ultralow carbon steel, comprising the following components in weight percentage: 3-10% of Na2O, 0-3% of Li2O, 3-8% of MgO, 5-15% of MnO, 0-8% of BaO, 4-12% of Al2O3, and impurities with a content of no more than 2%, the balance being CaO and SiO2, wherein the ratio of CaO/SiO2 is 0.8-1.3; the raw materials are mixed and then pre-melted; the pre-melted mold flux requires micro-adjusting according to the component deviation, and the ratio of the pre-melted material is not lower than 70%; then a carbonaceous material of 1-3% by the total weight of the mold flux is added and mixed so as to obtain the finished product mold flux. Said mold flux has a melting point of 1100-1200° C. and a viscosity of 0.2-0.6 Pa·s at 1300° C.

Abstract: The invention provides a fluoride-free continuous casting mold flux for low-carbon steel, comprising, based on weight, Na2O 5-10%, MgO 3-10%, MnO 3-10%, B2O3 3-10%, Al2O3?6%, Li2O<3%, C 1-3%, and the balance of CaO and SiO2 as well as inevitable impurities, wherein the ratio of CaO/SiO2 is 0.8˜1.3. The mold flux has a melting point of 95˜1150° C., a viscosity at 1300° C. of 0.1-0.3 Pa·s, and a crystallization rate of 10-50% as determined according to the method described in the specification for examining crystallization property. The boron-containing, fluoride-free flux developed according to the invention has a moderate crystallization rate, can be used in a crystallizer to control transfer of heat from molten steel effectively, and has been applied successfully in a low-carbon steel slab conticaster with a metallurgical effect that arrives at the level of a traditional fluoride-containing flux to full extent.