| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method of manufacturing hot-rolled steel plate by which highly accurate and stable cooling are obtained in runout cooling and the material of high strength and high toughness is secured even when winding temperature is in comparatively low temperature region of 450-550°C when manufacturing the hot-rolled steel plate of not less than 12 mm in the thickness of a product. <P>SOLUTION: When manufacturing the hot-rolled steel plate of not less than 12 mm in the thickness of the products, the thickness of a sheet bar is taken as 2.0-3.3 times of the thickness of the product, rolling is performed in an unrecrystalization temperature range with all the stands of a finishing mill 4 and also the conveying speed of the steel plate during run out cooling is set to not lower than 180 mpm. Runout cooling equipment 5 is a cooling equipment for performing the cooling of the upper surface of the steel plate 10 by a laminar system and divided into cooling equipment 6 on the upstream side and cooling equipment 7 on the downstream side and the flow rate of water per unit area of cooling water for performing the upper surface cooling of the steel plate 10 is 1.0-2.4 m<SP POS="POST">3</SP>/m<SP POS="POST">2</SP>min in the cooling equipment 6 on the upstream side and 0.5-1.0 m<SP POS="POST">3</SP>/m<SP POS="POST">2</SP>min in the cooling equipment on the downstream side. <P>COPYRIGHT: (C)2012,JPO&INPIT</p> |
