Patent ID: 9566625
Date: 2017-02-14
CPC Classifications: B21B

Claim:
1. An apparatus for cooling a hot-rolled steel sheet which cools a hot-rolled steel sheet hot-rolled using a finishing mill in a cooling section provided on a sheet-threading path, the apparatus comprising: a thermometer that measures a temperature of the hot-rolled steel sheet on a downstream side of the cooling section; a shape meter that measures a shape of the hot-rolled steel sheet on the downstream side of the cooling section; a top side cooling device that cools a top surface of the hot-rolled steel sheet in the cooling section; a bottom side cooling device that cools a bottom surface of the hot-rolled steel sheet in the cooling section; and a control device that controls at least one of an amount of heat dissipated from the top surface by cooling and an amount of heat dissipated from the bottom surface by cooling of the hot-rolled steel sheet in the cooling section by controlling the top side cooling device and the bottom side cooling device based on temperature measurement results of the hot-rolled steel sheet obtained from the thermometer and shape measurement results of the hot-rolled steel sheet obtained from the shape meter, wherein the control device includes: an average temperature computation unit that computes a chronological average value of the temperature of the hot-rolled steel sheet on the downstream side of the cooling section as an average temperature based on the temperature measurement results; a changing speed computation unit that computes a changing speed of the hot-rolled steel sheet on the downstream side of the cooling section based on the shape measurement results; a control direction-determining unit that, when upward in a vertical direction of the hot-rolled steel sheet is set as positive, in an area with a positive changing speed, in a case in which the temperature of the hot-rolled steel sheet is lower than an average temperature of a range of one or more cycles of a wave shape of the hot-rolled steel sheet, determines at least one of a direction in which the amount of heat dissipated from the top surface by cooling decreases and a direction in which the amount of heat dissipated from the bottom surface by cooling increases as a control direction, and, in a case in which the temperature of the hot-rolled steel sheet is higher than the average temperature, determines at least one of a direction in which the amount of heat dissipated from the top surface by cooling increases and a direction in which the amount of heat dissipated from the bottom surface by cooling decreases as the control direction, in an area with a negative changing speed, in a case in which the temperature of the hot-rolled steel sheet is lower than the average temperature, determines at least one of a direction in which the amount of heat dissipated from the top surface by cooling increases and a direction in which the amount of heat dissipated from the bottom surface by cooling decreases as the control direction, and, in a case in which the temperature of the hot-rolled steel sheet is higher than the average temperature, determines at least one of a direction in which the amount of heat dissipated from the top surface by cooling decreases and a direction in which the amount of heat dissipated from the bottom surface by cooling increases as the control direction; and a total amount of heat dissipated by cooling-adjusting unit that adjusts a total value of the amount of heat dissipated from the top surface by cooling and the amount of heat dissipated from the bottom surface by cooling of the hot-rolled steel sheet in the cooling section based on the control directions determined using the control direction-determining unit.