COOLING METHOD OF THICK STEEL PLATE AND PRODUCTION METHOD OF THICK STEEL PLATE, AND COOLING DEVICE FOR THICK STEEL PLATE

摘要

PROBLEM TO BE SOLVED: To provide a cooling method of a thick steel plate, enabling a temperature deviation of the thick steel plate after being sprinkled with cooling water to be suppressed .SOLUTION: There is provided the cooling method of a thick steel plate for sprinkling cooling water to the surface of the thick steel plate from a cooling header while conveying the hot-rolled thick steel plate. The cooling method comprises: a step of measuring a transverse-direction temperature distribution of the thick steel plate upstream from the cooling header; a step of estimating the temperature distribution of the thick steel plate after being sprinkled with cooling water based on the measured temperature distribution and a water quantity density distribution of the cooling header; and a step of adjusting the water quantity density distribution in the transverse-direction so as to minimize an estimated temperature deviation of the thick steel plate after being sprinkled with cooling water. The step of estimating the temperature distribution after the sprinkling of cooling water includes a step of calculating a transverse-direction distribution of height of a water film formed on the surface of the thick steel plate while taking the water quantity density distribution and a transverse-direction length of the thick steel plate into consideration, a step of calculating a distribution of a heat transmission coefficient by using the distribution of the water film height and a step of deriving the estimated temperature distribution after sprinkling of cooling water to the thick steel plate based on a measured value of the temperature distribution and the distribution of the heat transmission coefficient.