| 摘要 |
PURPOSE:To prevent the generation of throttlings in a strip by providing an air introducing device to a cooling water passage in a cooling roll in which the clearance part formed by an outer and an inner cylinders are used as the cooling water passage, and by changing over the cooling speed. CONSTITUTION:The cooling water passage 20 in the cooling roll 10 is formed in a single spiral shape, and the air introducing device 30 is provided to the inlet part of this passage 20. In oder to change the cooling roll 10 to a noncooling roll, first, an air opening-closing valve 311 is opened and valves 201, 200 are closed to stop the cooling water for passage for passage 20. Then, an air opening-closing valve 301 is opened to stream compressed air through an air introducing pipe 300, and the remaining cooling water in the passage 20 is discharged with a part of the compressed air from an air ejecting pipe 312 through an air discharge pipe 310. After the completion of the discharge, the valve 301 is closed, while the valve 311 on the other side is kept to be opened. In the same way, some of the numerous cooling rolls are adequately changed to noncooling rolls, and the cooling speed of the strip is easily changed thereby, and the generation of contractions in the strip in the cooling process is prevented. |
