A method for cooling a steel sheet, a cooling device for a steel sheet, and a method for manufacturing a steel sheet

摘要

An object of the present invention is to provide a method for cooling a steel sheet with little distortion, a cooling device for cooling the steel sheet, and a method for manufacturing a steel sheet in controlled cooling in which a steel sheet after hot rolling is cooled while restrained by a roll. Cooling of a steel sheet in which the steel sheet is conveyed in a restrained state by a plurality of rolls arranged at a predetermined pitch in the steel sheet conveying direction, and cooling water is sprayed on the upper and lower surfaces of the steel sheet by a cooling nozzle disposed between the plurality of rolls to cool the steel sheet In the method, a method for cooling a steel sheet in which the sheet is cooled at a sheet-threading speed (V) that satisfies the following formula (1). V > 2.21×10 -5 ×Cv×L 3 ×t -2 ×(24.2+204.3×(L/W) 2 ) -1 ... (1) However, in Formula (1), V: sheet-threading speed (m/s) Cv: cooling rate with respect to the average temperature of the steel sheet in the sheet thickness direction (°C/s) L: roll pitch (m) t: sheet thickness (m) W: The plate width (m).