Abstract: A method for evaluating center segregation of a continuous cast slab is provided. The method of the present invention includes (A) creating a center segregation image of a slab using an etching solution comprising a picric acid (C6H3N3O7), a cupric chloride (CuCl2), sodium laurylbenzenesulfonate (C18H29SO3Na) and the remainder of distilled water; and (B) evaluating the center segregation of a slab by scanning the image and applying the following Formula. The method creates an image of center segregation even for low-carbon steel having carbon (C) in an amount of 0.04 wt % or less as well as ultra low-sulfur steel having sulfur (S) in an amount of 50 ppm or less.

Abstract: The present invention relates to a mold powder supply apparatus using the waste heat of a tundish, which can collect waste heat from molten steel in the tundish, and preheat and dry mold powder. The mold powder supply apparatus using the waste heat of a tundish according to an embodiment of the present invention includes: a powder hopper that is mounted to a frame close to a tundish to absorb heat radiated from the top of the tundish, through one side; an agitator that agitates mold powder filled in the powder hopper; and a supply pipe that is connected to the bottom of the powder hopper to supply the powder hopper into a mold.

Abstract: Disclosed is a method of predicting surface quality of a thin slab hot rolled coil. The method includes calculating the Cu equivalent (Cu eq.) of molten steel, applying the calculated Cu equivalent of the molten steel into an equation: 120×(Cu equivalent)2?6×(Cu equivalent) to calculate a surface crack index, and predicting the generation of surface defect of the thin slab hot rolled coil by the surface crack index. A method of producing the thin slab hot rolled coil using the same is also provided. The surface crack defect of the thin slab hot rolled coil can be predicted by calculating the Cu equivalent of the molten steel, and thus a thin slab which meets the quality standard demanded by a consumer can be provided, and this results in increased productivity and product reliability.

Abstract: Disclosed is a method of predicting surface quality of a thin slab hot rolled coil. The method includes calculating the Cu equivalent (Cu eq.) of molten steel, applying the calculated Cu equivalent of the molten steel into an equation: 120×(Cu equivalent)2?6×(Cu equivalent) to calculate a surface crack index, and predicting the generation of surface defect of the thin slab hot rolled coil by the surface crack index. A method of producing the thin slab hot rolled coil using the same is also provided. The surface crack defect of the thin slab hot rolled coil can be predicted by calculating the Cu equivalent of the molten steel, and thus a thin slab which meets the quality standard demanded by a consumer can be provided, and this results in increased productivity and product reliability.

Abstract: A method for evaluating center segregation of a continuous cast slab is provided. The method of the present invention includes (A) creating a center segregation image of a slab using an etching solution comprising a picric acid (C6H3N3O7), a cupric chloride (CuCl2), sodium laurylbenzenesulfonate (C18H29SO3Na) and the remainder of distilled water; and (B) evaluating the center segregation of a slab by scanning the image and applying the following Formula. The method creates an image of center segregation even for low-carbon steel having carbon (C) in an amount of 0.04 wt % or less as well as ultra low-sulfur steel having sulfur (S) in an amount of 50 ppm or less.

Abstract: Disclosed herein is a method for reducing edge serration defects in a thin slab, including: reheating a thin slab having an alloy composition including carbon (C), niobium (Nb), aluminum (Al), iron (Fe) and inevitable impurities to uniformalize the thin slab into an austenite structure; controlling precipitates that occur in the reheated thin slab by controlling an temperature of the thin slab discharged from a heat-treatment furnace at a temperature at which niobium carbide (NbC) start to precipitate; and hot-rolling the thin slab. The method is advantageous in that the temperature of a thin slab discharged from a heat-treatment furnace is controlled, so that the edge serration defects in the thin slab can be reduced, thereby improving the productivity of the thin slab.

Abstract: The present invention relates to a mold powder supply apparatus using the waste heat of a tundish, which can collect waste heat from molten steel in the tundish, and preheat and dry mold powder. The mold powder supply apparatus using the waste heat of a tundish according to an embodiment of the present invention includes: a powder hopper that is mounted to a frame close to a tundish to absorb heat radiated from the top of the tundish, through one side; an agitator that agitates mold powder filled in the powder hopper; and a supply pipe that is connected to the bottom of the powder hopper to supply the powder hopper into a mold.