| 摘要 |
PURPOSE:To prevent generation of cooling strain by segmenting the range of cooling start temp. and stop temp. to plural temp. regions, and cooling a steel sheet while changing the spray pattern of cooling water from the top and bottom surfaces in the transverse direction of the steel sheet in accordance with the temp. region in each segment. CONSTITUTION:A high-temp. steel sheet formed by hot rolling is cooled with water from the top and bottom surfaces thereof. Water cooling of the high- temp. steel sheet is accomplished while the range of cooling start temp. and stop temp., for example, the water spray pattern in the distribution A of the water flow rate in the transverse direction, is changed to a pattern I , pattern IIand pattern III. More specifically, the pattern I is the same as in the conventional method but the distribution of the water flow at the edge is made slightly higher like in the pattern II unlike the pattern I in the temp. distribution in the transverse direction from the cooling start temp. of about 550 deg.C to the cooling stop temp. of about 300 deg.C. The distributions of the water flow in most of the transverse direction are made the same in the pattern III. |
