| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To uniformly cool a hot-rolled steel sheet which is hot-rolled by a finishing mill and is formed into a corrugated shape having corrugation height periodically varied in the rolling direction. <P>SOLUTION: On the basis of the heat transfer characteristic of a hot-rolled steel sheet to be cooled by an upper side cooling device on the upper surface side of the hot-rolled steel sheet and a lower side cooling device on the lower surface side of the hot-rolled steel sheet, which is obtained under the condition that the steepness of the corrugation of the hot-rolled steel sheet and the passing speed of the hot-rolled steel sheet are set to the predetermined values in advance, the upper-and-lower heat transfer coefficient ratio which is the ratio of the average heat transfer coefficients of the upper and lower surfaces of the hot-rolled steel sheet is changed in the predetermined cooling section. The relationship between the standard deviation of the temperature in the rolling direction of the hot-rolled steel sheet in that condition and the upper-and-lower heat transfer coefficient ratio is obtained by the diagram. Further, based on the diagram, the upper-and-lower heat transfer coefficient ratio in which the standard deviation of the temperature becomes minimum is derived. The hot-rolled steel sheet is cooled at the upper-and-lower heat transfer coefficient ratio under the assumption that the cooling heat-removal amount from the upper surface is equal to that of the lower surface of the hot-rolled steel sheet in the predetermined cooling zone in the case of the derived upper-and-lower heat transfer coefficient ratio. <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
