[Problem]

To provide a method for producing a metal ingot, which makes it possible to inhibit impurities contained in molten metal in a hearth from being mixed into the ingot.

[Solution]

A method for producing a metal ingot by using an electron-beam melting furnace having an electron gun and a hearth that accumulates a molten metal of a metal raw material, wherein the metal raw material is supplied to the position on a supply line disposed along a second side wall of the hearth that accumulates the molten metal of the metal raw material. A first electron beam is radiated along a first irradiation line that is disposed along the supply line and is closer to a central part of the hearth relative to the supply line on the surface of the molten metal. By this means, a surface temperature (T2) of the molten metal at the first irradiation line is made higher than an average surface temperature (T0) of the entire surface of the molten metal in the hearth, and in an outer layer of the molten metal, a first molten metal flow is formed from the first irradiation line toward the supply line.

A method for preparing high-purity nickel-based superalloy includes the steps of: performing electron beam smelting on small cylinders in a first water-cooled copper crucible after preheating an electron gun, and converging the beam to the edge of one side of the ingot; turning on the electron gun again after completely solidifying the ingot, the electron beam spot uniformly and slowly scanning a surface of the ingot from a side opposite to a final beam converging area of the ingot to the final beam converging area of the ingot to ensure that the alloy at a position scanned by the electron beam spot is completely melted, and stopping scanning once scanning to the final converging area of the ingot; casting the molten alloy in the first water-cooled copper crucible to the second water-cooled copper crucible; taking out the refined nickel-base superalloy after cooling down the electron beam melting furnace.

A method for preparing high-purity nickel-based superalloy includes the steps of: performing electron beam smelting on small cylinders in a first water-cooled copper crucible after preheating an electron gun, and converging the beam to the edge of one side of the ingot; turning on the electron gun again after completely solidifying the ingot, the electron beam spot uniformly and slowly scanning a surface of the ingot from a side opposite to a final beam converging area of the ingot to the final beam converging area of the ingot to ensure that the alloy at a position scanned by the electron beam spot is completely melted, and stopping scanning once scanning to the final converging area of the ingot; casting the molten alloy in the first water-cooled copper crucible to the second water-cooled copper crucible; taking out the refined nickel-base superalloy after cooling down the electron beam melting furnace.

In the field of refining metal melts or slags there is disclosed in particular a reactive material based on calcium aluminate and carbon, its process of preparation and various methods for refining metal melts using the same.

A method is disclosed for the operationally reliable production of a cold-rolled flat steel product of ?0.5 mm in thickness for deep-drawing and ironing applications. In the method, a steel melt which (in wt %) comprises up to 0.008% C, up to 0.005% Al, up to 0.043% Si, 0.15-0.5% Mn, up to 0.02% P, up to 0.03% S, up to 0.020% N and in each case optionally up to 0.03% Ti and up to 0.03% Nb and, as a remainder, iron and unavoidable impurities, is, with the omission of a Ca treatment, subjected to a secondary metallurgical treatment which, in addition to a vacuum treatment, comprises a ladle furnace treatment and during which the steel melt to be treated is kept under a slag, the Mn and Fe contents of which are, in sum total, <15 wt %. From the steel melt, a thin slab or a cast strip are produced, which are subsequently hot-rolled to form a hot strip with a thickness of <2.5 mm and wound to form a coil. Subsequently, the hot strips are cold-rolled to form a flat steel product of up to 0.5 mm in thickness.

Provided are a high-strength steel sheet having a specified chemical composition, in which a Mn-segregation degree in a region within 100 m from a surface thereof in a thickness direction is 1.5 or less, in a plane parallel to the surface of the steel sheet in a region within 100 m from the surface of the steel sheet in the thickness direction, the number of oxide-based inclusion grains having a grain long diameter of 5 m or more is 1000 or less/100 mm.sup.2, a proportion of the number of oxide-based inclusion grains having a chemical composition containing alumina of 50 mass % or more, silica of 20 mass % or less, and calcia of 40 mass % or less to the total number of oxide-based inclusions having a grain long diameter of 5 m or more is 80% or more, a specified metallographic structure, and a TS of 980 MPa or more, a high-strength galvanized steel sheet, and a manufacturing method thereof.

A system and method for continuous casting. The system includes a melt chamber, a withdrawal chamber, and a secondary chamber therebetween. The melt chamber can maintain a melting pressure and the withdrawal chamber can attain atmospheric pressure. The secondary chamber can include regions that can be adjusted to different pressures. During continuous casting operations, the first region adjacent to the melt chamber can be adjusted to a pressure that is at least slightly greater than the melting pressure; the pressure in subsequent regions can be sequentially decreased and then sequentially increased. The pressure in the final region can be at least slightly greater than atmospheric pressure. The differential pressures can form a dynamic airlock between the melt chamber and the withdrawal chamber, which can prevent infiltration of the melt chamber by non-inert gas in the atmosphere, and thus can prevent contamination of reactive materials in the melt chamber.

A method for producing ultra-thin hot-rolled strip steel, the method comprising the following process steps: A. a smelting process: feeding scrap steel into an induction electric furnace (1) for smelting so that the scrap steel melts into molten steel; B. a refining process: using a ladle refining furnace (2) and a ladle vacuum degassing furnace (3) to refine the molten steel; C. a continuous casting process: casting the refined molten steel into a cast strip blank that has a thickness of 1.6-2.5 mm by means of a dual-roller thin strip continuous casting system (4); D. a hot rolling process: directly feeding the cast strip blank that was cast in the continuous casting process to a single-stand hot rolling mill (9) for rolling to produce hot-rolled strip steel, the thickness of the hot-rolled strip steel being 0.8-1.5 mm; E. a cooling coiling process: performing atomizing cooling on the hot-rolled strip steel, and coiling after the strip steel temperature is controlled to be 400-750 C. The present method achieves an extremely compact, environmentally-friendly and economical ultra-thin hot-rolled strip steel production process flow, and achieves the environmentally-friendly and economical continuous production of metal plates and strips.

A method for producing ultra-thin hot-rolled strip steel, the method comprising the following process steps: A. a smelting process: feeding scrap steel into an induction electric furnace (1) for smelting so that the scrap steel melts into molten steel; B. a refining process: using a ladle refining furnace (2) and a ladle vacuum degassing furnace (3) to refine the molten steel; C. a continuous casting process: casting the refined molten steel into a cast strip blank that has a thickness of 1.6-2.5 mm by means of a dual-roller thin strip continuous casting system (4); D. a hot rolling process: directly feeding the cast strip blank that was cast in the continuous casting process to a single-stand hot rolling mill (9) for rolling to produce hot-rolled strip steel, the thickness of the hot-rolled strip steel being 0.8-1.5 mm; E. a cooling coiling process: performing atomizing cooling on the hot-rolled strip steel, and coiling after the strip steel temperature is controlled to be 400-750 C. The present method achieves an extremely compact, environmentally-friendly and economical ultra-thin hot-rolled strip steel production process flow, and achieves the environmentally-friendly and economical continuous production of metal plates and strips.

Provided are a method and a refining device for producing molten steel of outstanding cleanliness, and more particularly provides a method and device for refining inclusions by forming droplets from molten steel and dropping same into slag during pre-processing in a continuous casting process in a steel-making process. Also, provided is a method for producing high cleanliness molten steel comprising a molten-steel supply device for supplying molten steel and a molten-steel refining device for containing and refining molten steel poured into the molten-steel supply device, wherein the method comprises: a molten-steel pouring step in which molten steel is poured from the molten-steel supply device into the molten-steel refining device; a droplet-forming step in which the molten steel which has been poured in is formed into droplets in the molten-steel refining device; a slag-pass-through step in which the molten steel which has been formed into droplets is dropped so as to pass through slag; and an inclusion-removing step in which residual inclusions in the molten steel, which has been formed into droplets, are removed while passing through the slag.