Method for cooling hot-rolled steel strip

A method for cooling a hot-rolled steel strip after a finishing rolling in which a transportation speed varies, the method including:

• setting a transportation-speed changing schedule based on a temperature of a steel strip before the finishing rolling and a condition of the finishing rolling;
• performing a first cooling in which the hot-rolled steel strip is cooled under a film boiling state in a first cooling section;
• performing a second cooling in which the hot-rolled steel strip is cooled with a water amount density of not less than 2 m3/min/m2 in a second cooling section;
• and
• coiling the hot-rolled steel strip, wherein
• a cooling condition is controlled in the first cooling such that a target temperature T2a of the steel strip on an input side in the second cooling section before a change in a speed of rolling, a target temperature T2a′ of the steel strip on an input side in the second cooling section after a change in the speed of rolling, and a change amount ΔTx of an amount of cooling the hot-rolled steel strip in the second cooling section, the change amount being caused by the change in the speed of rolling, satisfy
• 0.8≦(T2a′−T2a)/ΔTx≦1.2 (Equation 1).