Abstract: A continuous casting apparatus for steel includes: a casting mold for casting a molten steel with a pair of long side walls and a pair of short side walls; a submerged entry nozzle which discharges the molten steel into the casting mold; and an electromagnetic stirring device which is disposed along each external surface of each of the long side walls and stirs an upper portion of the molten steel within the casting mold. A curved portion which is convexly curved toward the electromagnetic stirring device in plan view is formed at least at a position where the curved portion faces the submerged entry nozzle on each of the long side walls, and each of the long side walls including the curved portion has a uniform thickness.

Abstract: A continuous casting device for steel of the present invention includes a casting mold for casting a molten steel, a submerged entry nozzle, an electromagnetic stirring device, and an electromagnetic brake device. Further, a curved portion which is curved toward the electromagnetic stirring device is formed at least at a position where the curved portion faces the submerged entry nozzle, on each of the long side walls. Moreover, the horizontal distance between a top of the curved portion and the submerged entry nozzle in plan view is equal to or more than 35 mm and less than 50 mm.

Abstract: A continuous casting method of molten metal using electromagnetic force to improve the cast slab surface properties and reduce the nonmetallic inclusions and bubbles trapped inside the cast slab is provided. An alternating current is run through an electromagnetic coil arranged around a casting mold so as to surround a casting space to control the meniscus shape to improve the cast slab surface properties. The discharge ports of a submerged entry nozzle are oriented upward and the direction of the discharge flow from the discharge ports is above the intersection of the casting mold short side and meniscus.

Abstract: A continuous casting device for steel of the present invention includes a casting mold for casting a molten steel, a submerged entry nozzle, an electromagnetic stirring device, and an electromagnetic brake device. Further, a curved portion which is curved toward the electromagnetic stirring device is formed at least at a position where the curved portion faces the submerged entry nozzle, on each of the long side walls. Moreover, the horizontal distance between a top of the curved portion and the submerged entry nozzle in plan view is equal to or more than 35 mm and less than 50 mm.

Abstract: The present invention provides a continuous casting method of molten metal using electromagnetic force to improve the cast slab surface properties and reduce the nonmetallic inclusions and bubbles trapped inside the cast slab. An alternating current is run through an electromagnetic coil 4 arranged around a casting mold 1 so as to surround a casting space 8 to control the meniscus shape to improve the cast slab surface properties, the discharge ports 6 of a submerged entry nozzle 5 are made upward oriented, and the direction of the discharge flow 14 from the discharge ports 6 is made one to above the intersection A of the casting mold short side and meniscus. Due to this, the nonmetallic inclusions and bubbles in the discharge flow are absorbed by the continuous casting mold flux of the meniscus 11 at the part of the meniscus reached.

Abstract: A cast slab has a negative segregation zone composed of a multilayer structure of negative segregation layers disposed between dendrite or crystalline layers. The dendrite or crystalline layers are a deflection structure caused by vibration during formation of the cast slab. The negative segregation layers have a distance between them of not more than 2 mm and the number of negative segregation layers is not less than 3. The cast slab has an equi-axed crystal ratio of not less than 50% inside the multilayer negative segregation zone.

Abstract: In order to quickly and economically evaluate cleanliness of a metal with high representativity when quantities, compositions, etc., of non-metallic inclusion particles existing in a metal and resulting in product defects are evaluated by a sample collected during the production process of the metal, the present invention provides an evaluation method involving the steps of levitation-melting a metal piece for a predetermined time by cold crucible levitation-melting means, discharging non-metallic inclusion particles contained in the metal piece to the surface of a molten metal, and directly analyzing a curved and non-smooth sample surface after solidification by a fluorescent X-ray analysis method using an energy dispersion type spectroscope, or by other chemical or physical measurements, to measure or analyze the quantities of elements constituting the non-metallic inclusion particles and to determine quantity of the non-metallic inclusions.

Abstract: The present invention provides a continuous casting method in which vibration is given to molten metal by a shifting magnetic field so that the equi-axed crystal ratio can be enhanced and the equi-axed crystals can be made fine without generating surface defects caused by powder trapping. Further, the present invention provides an apparatus to which the continuous casting method is applied. Furthermore the present invention provides a cast slab produced by the above method and apparatus.

Abstract: In order to quickly and economically evaluate cleanliness of a metal with high representativity when quantities, compositions, etc., of non-metallic inclusion particles existing in a metal and resulting in product defects are evaluated by a sample collected during the production process of the metal, the present invention provides an evaluation method involving the steps of levitation-melting a metal piece for a predetermined time by cold crucible levitation-melting means, discharging non-metallic inclusion particles contained in the metal piece to the surface of a molten metal, and directly analyzing a curved and non-smooth sample surface after solidification by dissolving the surface and extracting and filtering the inclusions to measure or analyze the quantities of elements constituting the non-metallic inclusion particles and to determine quantity of the non-metallic inclusions.

Abstract: The present invention provides a continuous casting method in which vibration is given to molten metal by a shifting magnetic field so that the equi-axed crystal ratio can be enhanced and the equi-axed crystals can be made fine without generating surface defects caused by powder trapping. Further, the present invention provides an apparatus to which the continuous casting method is applied. Furthermore, the present invention provides a cast slab produced by the above method and apparatus.

Abstract: The present invention provides a continuous casting method in which vibration is given to molten metal by a shifting magnetic field so that the equi-axed crystal ratio can be enhanced and the equi-axed crystals can be made fine without generating surface defects caused by powder trapping. Further, the present invention provides an apparatus to which the continuous casting method is applied. Furthermore, the present invention provides a cast slab produced by the above method and apparatus.

Abstract: An object of the present invention is to provide a process for continuously casting a molten metal which process suppresses the instability of the initial solidification and stably improves the lubrication and the surface properties of the cast metal, and an apparatus therefore, in the process for continuously casting a molten metal an alternating current is applied to an electromagnetic coil which is provided so that it surrounds a continuous casting mold wall or is embedded in the side wall of the mold, whereby an electromagnetic force is exerted on the molten metal poured into the mold which either oscillates in a constant mode or does not oscillate and is starting to be solidified the process of the present invention also comprises periodically changing the amplitude or waveform of the alternating current to be applied, and the apparatus of the present invention is used for the process.

Abstract: In order to quickly and economically evaluate cleanliness of a metal with high representativity when quantities, compositions, etc., of non-metallic inclusion particles existing in a metal and resulting in product defects are evaluated by a sample collected during the production process of the metal, the present invention provides an evaluation method involving the steps of levitation-melting a metal piece for a predetermined time by cold crucible levitation-melting means, discharging non-metallic inclusion particles contained in the metal piece to the surface of a molten metal, and directly analyzing a curved and non-smooth sample surface after solidification by a fluorescent X-ray analysis method using an energy dispersion type spectroscope, or by other chemical or physical measurements, to measure or analyze the quantities of elements constituting the non-metallic inclusion particles and to determine quantity of the non-metallic inclusions.

Abstract: A rapid analysis device for analyzing nonmetallic inclusions in steel by a cold crucible method is combined with a mathematical model, and the quality of cast steel is predicted online by simulating the behavior. of the nonmetallic inclusions by calculation. Further, continuous casting process variables are controlled to minimize the amount of nonmetallic inclusions in the cast steel.

Abstract: A method and an apparatus for continuously casting a metal slab made of steel are provided for uniformly circulating molten metal on a meniscus in a mold. The cast metal slab has no surface defect such as a slitting. On the meniscus, the method and apparatus operates to generate electromagnetic stirring thrusts along two long mold sides, these thrusts being opposed to each other. The thrust oriented from a dipping nozzle to the short mold side is made larger than the thrust oriented from the short mold side to the dipping nozzle. A circuit for connecting each coil of a shifting field electromagnetic stirring coil part with a three-phase power supply is symmetric to another circuit with respect to the dipping nozzle. The circuit is divided into two parts along each long mold side. The divided circuit parts are located in parallel but have respective impedances.

Abstract: An object of the present invention is to provide a process for continuously casting a molten metal which process suppresses the instability of the initial solidification and stably improves the lubrication and the surface properties of the cast metal, and an apparatus therefor, in the process for continuously casting a molten metal an alternating current is applied to an electromagnetic coil which is provided so that it surrounds a continuous casting mold wall or is embedded in the side wall of the mold, whereby an electromagnetic force is exerted on the molten metal poured into the mold which either oscillates in a constant mode or does not oscillate and is starting to be solidified the process of the present invention also comprises periodically changing the amplitude or waveform of the alternating current to be applied, and the apparatus of the present invention is used for the process.

Abstract: The present invention provides a method, for regulating the flow of a molten steel within a mold by taking advantage of a direct current magnetic field, comprising the step of carrying out continuous casting while regulating the flow of a molten steel, delivered through a nozzle, by applying a direct current magnetic field having a substantially uniform magnetic flux distribution over the whole width direction of the mold, characterized in that the flow velocity of a meniscus on the surface of the molten steel within the mold is regulated in a range of from 0.20 to 0.40 m/sec by regulating the molten steel delivery angle of the nozzle, the position of the magnetic field, and the magnetic flux density.

Abstract: In a continuous casting process in a twin-roll system, a gap is provided between end faces of cooling rolls and side gates or between the circumferential surface of the cooling rolls and side faces of the side gates. A DC magnetic field is applied to the molten metal in a pouring basin in the vicinity of the side gates in a vertical direction to the molten metal and direct current (DC) is intensively fed to the end portion of the molten metal to generate an electromagnetic force mainly at a corner portion of the molten metal. The electromagnetic force is directed toward the center portion of the molten metal, and thereby prevents leakage of molten metal from the gap, penetration into the gap or the formation of hot bands. In order to intensively feed the direct current to the end portion of the molten metal, an electrode is placed in sliding contact with the end face of the cooling roll.