Abstract: A breakout prediction method includes: a step of inputting a dimension of a solid product withdrawn from a mold in a continuous casting machine; a step of detecting a temperature of the mold by a plurality of thermometers embedded in the mold; a step of executing interpolation processing on the detected temperatures detected by the plurality of thermometers according to the dimension of the solid product; a step of calculating, based on the temperatures calculated by executing the interpolation processing, a component in a direction orthogonal to an influence coefficient vector obtained by principal component analysis as a degree of deviation from during a normal operation in which a breakout has not occurred; and a step of predicting a breakout based on the degree of deviation.

Abstract: A continuous casting method of steel of continuously casting a slab by using a vertical liquid bending type continuous casting machine. The method includes, while performing continuous casting by using an in-mold electromagnetic stirring device, applying an alternating-current moving magnetic field that moves in a width direction of a mold to molten steel inside the mold, inducing a swirling flow in the molten steel, and stirring the molten steel. A travel speed of the alternating-current moving magnetic field calculated by a specified formula is in a range of 0.20 to 1.50 m/s.

Abstract: 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.

Abstract: A method for continuously casting steel capable of reducing center segregation that occurs in a slab. In a section in a continuous casting machine in a slab withdrawal direction, a section from a start point at which the average value of solid phase ratios along a thickness direction at a widthwise center of a slab is within a range of 0.4 or more and 0.8 or less to an end point at which the average value of solid phase ratios along the thickness direction at the widthwise center of the slab is greater than the average value of solid phase ratios at the start point and is 1.0 or less is set as a first section. The slab is cooled by water in the first section at a water flow rate per surface area of the slab within a range of 50 L/(m2×min) or more and 2,000 L/(m2×min) or less.

Abstract: A device includes: an input device configured to receive an input of measurement results of a temperature and components of molten steel in a tundish of continuous casting facilities, measurement results of a width, a thickness, and a casting speed of a cast slab casted in the continuous casting facilities, and molten steel flow rate distribution in a mold; a model database configured to store a model expression and a parameter related to solidification reaction of molten steel in the mold; a convertor configured to convert a molten steel flow rate in the mold into a heat conductivity parameter; and a calculator configured to estimate a solidified shell thickness in the mold based on temperature distribution of the mold and steel in the mold calculated by solving a three-dimensional transient heat conduction equation using the measurement results.

Abstract: A breakout prediction method includes: a step of inputting a dimension of a solid product withdrawn from a mold in a continuous casting machine; a step of detecting a temperature of the mold by a plurality of thermometers embedded in the mold; a step of executing interpolation processing on the detected temperatures detected by the plurality of thermometers according to the dimension of the solid product; a step of calculating, based on the temperatures calculated by executing the interpolation processing, a component in a direction orthogonal to an influence coefficient vector obtained by principal component analysis as a degree of deviation from during a normal operation in which a breakout has not occurred; and a step of predicting a breakout based on the degree of deviation.

Abstract: A continuously casting method including arranging temperature measuring elements according to specified conditions, selecting as evaluation targets for temperatures of copper plates on a wide face of mold values measured by the temperature measuring elements arranged closer to a center in a width direction of a cast slab than short sides of the cast slab under continuous casting at levels of 50 mm or more lower in a slab withdrawal direction than a meniscus of a molten steel in a mold, and adjusting a casting condition such that a standard deviation of the values measured over the width direction of the copper plates on the wide face of mold at a same level in the slab withdrawal direction is 20° C. or lower.

Abstract: An in-mold solidified shell thickness estimation apparatus includes: an input device; a model database configured to store a model formula and a parameter related to a solidification reaction of a molten steel inside a mold of a continuous casting facility; and a heat transfer model calculator configured to estimate an in-mold solidified shell thickness by calculating temperature distributions of the mold and of the molten steel inside the mold by solving a three-dimensional unsteady heat transfer equation. The heat transfer model calculator is configured to correct errors in a temperature of a mold copper plate and in an amount of heat removed from the mold, by correcting an overall heat transfer coefficient between the mold copper plate and the solidified shell.

Abstract: A method for continuously casting steel capable of reducing center segregation that occurs in a slab. In a section in a continuous casting machine in a slab withdrawal direction, a section from a start point at which the average value of solid phase ratios along a thickness direction at a widthwise center of a slab is within a range of 0.4 or more and 0.8 or less to an end point at which the average value of solid phase ratios along the thickness direction at the widthwise center of the slab is greater than the average value of solid phase ratios at the start point and is 1.0 or less is set as a first section. The slab is cooled by water in the first section at a water flow rate per surface area of the slab within a range of 50 L/(m2×min) or more and 2,000 L/(m2×min) or less.

Abstract: A device includes: an input device configured to receive an input of measurement results of a temperature and components of molten steel in a tundish of continuous casting facilities, measurement results of a width, a thickness, and a casting speed of a cast slab casted in the continuous casting facilities, and molten steel flow rate distribution in a mold; a model database configured to store a model expression and a parameter related to solidification reaction of molten steel in the mold; a convertor configured to convert a molten steel flow rate in the mold into a heat conductivity parameter; and a calculator configured to estimate a solidified shell thickness in the mold based on temperature distribution of the mold and steel in the mold calculated by solving a three-dimensional transient heat conduction equation using the measurement results.

Abstract: A continuously casting method including arranging temperature measuring elements according to specified conditions, selecting as evaluation targets for temperatures of copper plates on a wide face of mold values measured by the temperature measuring elements arranged closer to a center in a width direction of a cast slab than short sides of the cast slab under continuous casting at levels of 50 mm or more lower in a slab withdrawal direction than a meniscus of a molten steel in a mold, and adjusting a casting condition such that a standard deviation of the values measured over the width direction of the copper plates on the wide face of mold at a same level in the slab withdrawal direction is 20° C. or lower.

Abstract: 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.

Abstract: Provided is a non-oriented electrical steel sheet having such a low Al concentration so that it is excellent in terms of the recycling efficiency of scrap iron and having a high magnetic flux density and low iron loss. The non-oriented electrical steel sheet according to the present invention has a chemical composition containing C; 0.0050 mass % or less, Si; 1.5 mass % to 5.0 mass %, Mn; 0.2 mass % to 3.0 mass %, sol.Al; 0.0030 mass % or less, P; 0.2 mass % or less, S; 0.0050 mass % or less, N; 0.0040 mass % or less, T.Ca; 0.0010 mass % to 0.0080 mass %, T.O; 0.0100 mass % or less, REM; 0.0001 mass % to 0.0050 mass %, and a balance of Fe and inevitable impurities, in which a value of a mass-related fractional expression ((T.Ca+REM)/(T.O+S)), which is a relational expression for the masses of the four constituents described above, that is, T.Ca, REM, T.O, and S, is 0.4 or more.

Abstract: In producing high-quality steel with use of copper-containing steel scraps as an iron source, the copper-containing steel scraps are melted with addition of carbon to produce hot metal for steelmaking, then, copper contained in the hot metal is removed by sulfur-containing flux, and sulfur contained in the hot metal is removed. With this method, the copper in the steel scraps can be removed efficiently and without the need for large facilities. Preferably, the sulfur-containing flux used is flux having Na2S as the main component. The treatment for removing copper in the hot metal is preferably carried out with use of refining equipment with mechanical stirrer or by the flux injecting method. Besides, it is preferable that a shaft furnace having a coke bed formed inside is used to produce hot metal having a higher concentration of sulfur for the copper removal treatment.