| 摘要 |
PURPOSE:To make it possible to continuously anneal a soft cold rolled steel plate for drawing with excellent cold moldability and a high tensile cold rolled steel plate by the same apparatus through a mechanism wherein a gas jet cooling portion and a water cooling portion are provided together to a cooling mechanism within a continuous annealing apparatus of a steel plate and these portions are used by switching appropriately. CONSTITUTION:After a steel plate S is passed through a heating furnace 8 and a homogenously heating furnace 9 to heat said steel plate to about A1 transformation point, said steel plate S is passed through a gas jet cooling portion 10, a water cooling portion 11 to be cooled and entered into a water cooling apparatus 20, a drying apparatus 21 through a reheating furnace 16, an over ageing treatment zone 17, a gas cooling zone 18, thereafter passed through a skin pass machine 22 and wound on a reel 27. In this case, in annealing a high tensile steel plate, said steel plate is passed through the gas jet cooling portion 10 and the water cooling portion 11 and, in case of annealing a soft steel plate for drawing, said steel plate is cooled only by the gas jet cooling after cooling water within the water cooling chamber 12 is exhausted by operating a valve and said chamber 12 is filled by a gaseous cooling medium to stop the water cooling. The exhausted cooling water is transferred to a warm water pit and used by circulating when a high tensile steel plate is annealed. |
