Abstract: The present cooling device includes: when cooling regions obtained by dividing an entire cooling region into a plurality of portions in a steel sheet conveyance direction and three or more portions in a width direction are set as divided cooling surfaces, a cooling water nozzle 23 and a switching device that switches between collision and non-collision of cooling water jetted from the cooling water nozzle 23 with the divided cooling surface, the cooling water nozzle 23 and the switching device provided for each of the divided cooling surfaces; and a control device that controls operation of the switching device based on a width-direction temperature distribution. The cooling water nozzle 23 has a jet axis P inclined with respect to a vertical line to the entire cooling region when viewed in the steel sheet conveyance direction, and the cooling water goes to the side opposite to the cooling water nozzle 23 in the width direction after colliding with the divided cooling surface.

Abstract: Provided is a cooling device, where a hot-finish-rolling mill includes a plurality of nozzles which spray cooling water toward one of or both of upper and lower surfaces of a hot-rolled steel sheet just after rolled by rolling stands, the nozzles are provided on the inside of the upper and lower guides or adjoining to the guides on a downstream side, and a nozzle spray distance changes depending on a position of the nozzle in a rolling direction, wherein a spray angle of the nozzle at a position whose nozzle spray distance is the largest is smaller than a spray angle of the nozzle at a position whose nozzle spray distance is the smallest, and the spray angle of the nozzle becomes the same or smaller as the nozzle spray distance becomes large.

Abstract: The present cooling device includes: when cooling regions obtained by dividing an entire cooling region into a plurality of portions in a steel sheet conveyance direction and three or more portions in a width direction are set as divided cooling surfaces, a cooling water nozzle 23 and a switching device that switches between collision and non-collision of cooling water jetted from the cooling water nozzle 23 with the divided cooling surface, the cooling water nozzle 23 and the switching device provided for each of the divided cooling surfaces; and a control device that controls operation of the switching device based on a width-direction temperature distribution. The cooling water nozzle 23 has a jet axis P inclined with respect to a vertical line to the entire cooling region when viewed in the steel sheet conveyance direction, and the cooling water goes to the side opposite to the cooling water nozzle 23 in the width direction after colliding with the divided cooling surface.

Abstract: Provided is a cooling device, where a hot-finish-rolling mill includes a plurality of nozzles which spray cooling water toward one of or both of upper and lower surfaces of a hot-rolled steel sheet just after rolled by rolling stands, the nozzles are provided on the inside of the upper and lower guides or adjoining to the guides on a downstream side, and a nozzle spray distance changes depending on a position of the nozzle in a rolling direction, wherein a spray angle of the nozzle at a position whose nozzle spray distance is the largest is smaller than a spray angle of the nozzle at a position whose nozzle spray distance is the smallest, and the spray angle of the nozzle becomes the same or smaller as the nozzle spray distance becomes large.