A method of producing an exothermic mold powder in a form of sprayed granules of the present invention includes spray-drying into granules, an aqueous slurry containing: a raw material blend; and a metal silicon powder and/or a silicon alloy powder, the method comprising adjusting the pH of the aqueous slurry to 13 or less.

A mold powder which prevents surface defects from occurring on a surface of a cast slab of Al-containing hypo-peritectic steel having Al: 0.2% to 2.0%, by mass %, and, in a hypo-peritectic region, C: 0.08% to 0.17%, by mass %. The mold powder includes CaO, SiO.sub.2, Na.sub.2O, Li.sub.2O, F, and C. Li.sub.2O/Na.sub.2O is 0.6 or more, 1.0+0.05?Al?CaO/SiO.sub.2?2.0?0.35?Al, 10<Li.sub.2O+0.5?Na.sub.2O+0.8?F<20, and 1.00?F/(Li.sub.2O+0.5?Na.sub.2O+1.46)?1.24 are satisfied where Al is content by mass % of molten steel, and respective contents of the remaining elements are by mass %. A viscosity of the mold powder at 1,300? C. is in a range of 0.05 Pa.Math.s to 0.20 Pa.Math.s, and a crystallization temperature of the mold powder is in a range of 1,100? C. to 1,250? C.

A mold powder which prevents surface defects from occurring on a surface of a cast slab of Al-containing hypo-peritectic steel having Al: 0.2% to 2.0%, by mass %, and, in a hypo-peritectic region, C: 0.08% to 0.17%, by mass %. The mold powder includes CaO, SiO.sub.2, Na.sub.2O, Li.sub.2O, F, and C. Li.sub.2O/Na.sub.2O is 0.6 or more, 1.0+0.05?Al?CaO/SiO.sub.2?2.0?0.35?Al, 10<Li.sub.2O+0.5?Na.sub.2O+0.8?F<20, and 1.00?F/(Li.sub.2O+0.5?Na.sub.2O+1.46)?1.24 are satisfied where Al is content by mass % of molten steel, and respective contents of the remaining elements are by mass %. A viscosity of the mold powder at 1,300? C. is in a range of 0.05 Pa.Math.s to 0.20 Pa.Math.s, and a crystallization temperature of the mold powder is in a range of 1,100? C. to 1,250? C.

A control method for a continuous casting machine, includes: estimating, by on-line real-time system, a flow state of molten steel in a mold by using an operation condition of a continuous casting machine and temperature data on the molten steel in the mold; calculating, by on-line real-time system, a molten steel flow index based on the estimated flow state of the molten steel, the molten steel flow index being a factor of mixing of an impurity into a casting inside the mold; and controlling the operation condition of the continuous casting machine such that the calculated molten steel flow index is within an appropriate range.

Improved casting powders and improved casting slags enable production of steels having high aluminum contents of greater than or equal to 1% by weight and, in some cases, high manganese content of greater than or equal to 15% by weight. In some examples, such steels may also or alternatively include greater than or equal to 0.2% by weight titanium. The casting slag may result from a casting powder that comprises CaO and Al.sub.2O.sub.3 components essentially in the form of prefused calcium aluminate. Methods for casting steel, including methods for continuously casting steel, are also disclosed based on the use of the disclosed casting powders or casting slags.

Improved casting powders and improved casting slags enable production of steels having high aluminum contents of greater than or equal to 1% by weight and, in some cases, high manganese content of greater than or equal to 15% by weight. In some examples, such steels may also or alternatively include greater than or equal to 0.2% by weight titanium. The casting slag may result from a casting powder that comprises CaO and Al.sub.2O.sub.3 components essentially in the form of prefused calcium aluminate. Methods for casting steel, including methods for continuously casting steel, are also disclosed based on the use of the disclosed casting powders or casting slags.

A method of producing an exothermic mold powder in a form of sprayed granules of the present invention includes spray-drying into granules, an aqueous slurry containing: a raw material blend; and a metal silicon powder and/or a silicon alloy powder, the method comprising adjusting the pH of the aqueous slurry to 13 or less.

A method of producing an exothermic mold powder in a form of sprayed granules of the present invention includes spray-drying into granules, an aqueous slurry containing: a raw material blend; and a metal silicon powder and/or a silicon alloy powder, the method comprising adjusting the pH of the aqueous slurry to 13 or less.

A mold flux is used in continuous casting of Ti-containing hypo-peritectic steel so as to prevent longitudinal cracks from forming on a surface of a slab. The mold flux contains CaO, SiO.sub.2, an alkali metal oxide and a fluorine compound as major components. f(1), f(2) and f(3), which are calculated from the initial chemical composition, are (1.10.5T) to (1.90.5T), 0.05 to 0.40 and 0 to 0.40, respectively, if the Ti content of the molten steel (mass %) is T. The TiO.sub.2 content in the melting state during the casting is no more than 20 mass % and the ratio of the first peak height of perovskite to the first peak height of cuspidine in the mold flux film is no more than 1.0.

A mold flux is used in continuous casting of Ti-containing hypo-peritectic steel so as to prevent longitudinal cracks from forming on a surface of a slab. The mold flux contains CaO, SiO.sub.2, an alkali metal oxide and a fluorine compound as major components. f(1), f(2) and f(3), which are calculated from the initial chemical composition, are (1.10.5T) to (1.90.5T), 0.05 to 0.40 and 0 to 0.40, respectively, if the Ti content of the molten steel (mass %) is T. The TiO.sub.2 content in the melting state during the casting is no more than 20 mass % and the ratio of the first peak height of perovskite to the first peak height of cuspidine in the mold flux film is no more than 1.0.