A cooling roll including an axle and a sleeve, the sleeve having a length and a diameter and being structured as follows: an inner cylinder, a plurality of magnets disposed along at least a portion of the inner cylinder length, each magnet being defined by a width, a height and a length, a cooling system surrounding at least a portion of the plurality of magnets, the cooling system and the plurality of magnets being separated by a gap defined by a height, the gap height being the smallest distance between a magnet and the cooling system above, the magnets having a width such that the following formula is satisfied:
gap height×1.1≤magnet width≤gap height×8.6.

A hearth roll for a continuous annealing furnace, the hearth roll comprising a thermal spray coating on a surface of the hearth roll, wherein the thermal spray coating comprises main components consisting of a Co-based alloy, a carbide of a transition metal, and a double oxide; and impurities, the double oxide consists of one or two types of a first double oxide consisting of Al and a rare earth element and a second double oxide consisting of a transition metal and a rare earth element, and when the main components are 100 mass %, a content of the Co-based alloy is 25 mass % or more and 50 mass % or less, a content of the carbide is 5 mass % or more and 30 mass % or less, and a content of the double oxide is 20 mass % or more and 45 mass % or less.

The steel sheet of the present invention has a steel microstructure containing, in area fraction, martensite: from 20% to 100%, ferrite: from 0% to 80%, and another metal phase: 5% or less, and in which a ratio of a dislocation density in metal phases on a surface of the steel sheet to a dislocation density in the metal phases in a thicknesswise central portion of the steel sheet is from 30% to 80%. The maximum amount of warpage of the steel sheet when the steel sheet is sheared to a length of 1 m in a rolling direction is 15 mm or less.

The steel sheet of the present invention has a steel microstructure containing, in area fraction, martensite: 20% to 100%, ferrite: 0% to 80%, and another metal phase: 5% or less, in which, on a surface of the steel sheet, a ratio of dislocation density in metal phases at a widthwise edge of the steel sheet to dislocation density in the metal phases at a widthwise center of the steel sheet is 100% to 140%, and, at a thicknesswise center of the steel sheet, a ratio of dislocation density in the metal phases at the widthwise edge of the steel sheet to dislocation density in the metal phases at the widthwise center of the steel sheet is 100% to 140%. The maximum amount of warpage of the steel sheet when the steel sheet is sheared to a length of 1 m in a rolling direction is 15 mm or less.

To provide a roller scraper capable of having a long service life. A roller scraper that removes attached substances on a surface of a roller, the roller scraper including a scraper main body that is supported on a floor portion and a scraping claw that is disposed in such a manner as to project in a width direction of the scraper main body. The scraping claw is placed against the roller in such a manner as to be in contact with the surface of the roller, and an opening is formed in the scraper main body.

A method for manufacturing a metal sheet comprising pinching the metal sheet in rapid quenching between a pair of pinch rolls in the range where the temperature of the metal sheet is from (T.sub.Ms+150) (° C.) to (T.sub.Mf−150) (° C.), wherein the Ms temperature of the metal sheet is T.sub.Ms (° C.) and the Mf temperature thereof is T.sub.Mf (° C.), as well as a rapid quenching unit comprising a pair of pinch rolls capable of use in such a method.

The invention concerns a method for accentuating the orientation of the grains of a continuous steel sheet (1), in particular for producing electrical sheet steel, said method involving, during the movement of the steel sheet (1) in the longitudinal direction of same, a longitudinal stretching of the steel sheet (1) in a stretch region (1d) in which the steel sheet (1) moves at a temperature of between approximately 750° C. and approximately 900° C. The invention also concerns a device for implementing said method in which the stretching is carried out by two tensioning blocks (41, 42) comprising traction rollers arranged to move and guide the steel sheet (1). The invention further concerns a facility for producing electrical sheet steel comprising a line comprising a rolling mill and on which said method and said device are implemented downstream from the rolling mill.

Provided is a hearth roll for supporting and conveying a steel sheet in a continuous annealing furnace, wherein all of a shaft portion and a roil main body are made from one or more ceramic materials, preferably constituted with concentric ceramic layers of different ceramic materials centering on the rotation shaft of the roll. The hearth roll has not only an excellent pickup resistance but also a long roll life free from maintenance for long periods. Also provided is a continuous annealing facility using the hearth roll in at least one of a heating zone, a soaking zone and a cooling zone.

The present invention provides a hearth roll for heat treatment furnaces, which has excellent build-up resistance, has a hexavalent-chromium-free thermal spray coating film formed on the roll surface thereof and is safe for the environment. A method for manufacturing a hearth roll for continuous annealing furnaces includes a first step of applying an aqueous solution containing chromium phosphate onto a thermal spray coating film formed on the roll surface of a hearth roll or impregnating the thermal spray coating film with the aqueous solution; and a second step of burning the hearth roll.

A heat treatment device for a thermal treatment of a workpiece is provided with a housing that houses a chamber for accommodating the workpiece for the thermal treatment. A first roller supports the workpiece and moves the workpiece in a moving direction. A first brush seal is provided, wherein the first roller and the first brush seal are arranged relative to each other such that a first side of the workpiece contacts the first roller and a second side of the workpiece that is opposed to the first side contacts the first brush seal such that the first roller and the first brush seal then seal at least a first section of the chamber from a second section of the chamber.