METHOD FOR COOLING HOT-ROLLED STEEL PLATE

摘要

The present invention provides 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 on the basis of 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, in which a cooling condition is controlled in the first cooling so as to satisfy 0.8 ≤ (T2a' - T2a)/ΔTx ≤ 1.2.