Method of cooling control for steel plate, cooling control device, and method of manufacturing steel plate

A system comprising:

• a cooling control device for a steel plate performing cooling control while making the steel plate pass through a cooling zone in a conveyance direction;
• and
• a shape measuring meter arranged at an outgoing side of the cooling zone, wherein
• the cooling control device includes:
• an upper/lower water ratio determination unit configured to determine an upper/lower water ratio with respect to a steel plate to be cooled in such a manner that a curvature of the steel plate to be cooled is within a target permissible range, based on only (i) a past operating condition of a steel plate, (ii) a past upper/lower water ratio with respect to the steel plate when cooling under the past operating condition of the steel plate has been implemented, and (iii) a past curvature of the steel plate converted by the following equation based on a past C-warping amount of the steel plate immediately after being cooled in the cooling zone measured by the shape measuring meter a when the cooling under the past operating condition of the steel plate has been implemented:
• k=2×δ/((w/2)2+δ2), wherein k:
• the curvature of the steel plate, δ:
• the C-warping amount of the steel plate, and w:
• a plate width of the steel plate, and
• a cooling water amount adjustment unit configured to adjust an amount of cooling water to be blown onto the steel plate to reach the upper/lower water ratio determined by the upper/lower water ratio determination unit, wherein
• the shape measuring meter is configured to measure the past C-warping amount of the steel plate without measuring an upper surface temperature and a lower surface temperature of the steel plate, and
• the upper/lower water ratio determination unit is configured to determine the upper/lower water ratio without taking into consideration the upper surface temperature and the lower surface temperature of the steel plate.