| 摘要 |
In the event of cooling a steel sheet to a preset cooling termination temperature, the quantity of cooling water jetted from superior and inferior faces of a cooling unit is rapidly controlled to thereby prevent with high precision any deterioration of configuration of steel sheet attributed to a difference of cooling rate between the superior surface and inferior surface thereof. In particular, on the basis of measurement value by means of a cooling entrance side thermometer installed on the entrance side of cooling unit, cooling conditions required for lowering the temperature of steel sheet at the time of passage through the interior of the cooling unit to given temperature of the steel sheet are computed for multiple positions inside the cooling unit, thereby establishing a cooling schedule. From established temperature and cooling inferior-zone water quantity density, there is computed a coefficient of heat transfer. From the computed heat transfer coefficient, there is computed a cooling superior-zone water quantity density. On the basis of the ratio between cooling inferior-zone water quantity density and cooling superior-zone water quantity density, there is controlled the cooling water quantity of the cooling unit. Thus, there can be saved the volume of computation required for controlling of the quantity of cooling water jetted from superior and inferior faces of the cooling unit in order to cool the steel sheet to the preset cooling termination temperature.
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