VERTICAL COOLING DEVICE FOR STEEL PLATE, AND METHOD OF MANUFACTURING GALVANIZED STEEL PLATE USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a vertical cooling device for steel plate that can properly prevent stretcher strain from being generated in a cooling process after galvanization, and a method of manufacturing a galvanized steel plate using the same.SOLUTION: A vertical cooling device for steel plate includes: a box which has openings at the top and bottom and in which a steel plate travels upward or downward; many nozzle headers with spray nozzles arranged along a length and a width of the steel plate to jet water mist to the steel plate; and a seal mechanism which prevents water from leaking from the lower opening. The vertical cooling device for steel plate has an outlet for discharging droplets in the box, and the nozzle headers are so installed separately from one another so as to have gaps for discharge of 30% or larger in opening area rate. The opening area rate is the ratio of the total area of the gaps between the nozzle headers and box area in cross-section area formed by nozzle headers on one surface side viewed from the steel plate side and the box, and found from (total area of gaps between nozzle headers/box area)×100.