| 摘要 |
PURPOSE:To perform hot finish rolling so as to prevent a collision flaw of work roll and a top mark generating in the surface of strip caused by the collision flaw, by changing the flow rate of cooling water, required for the 1st rolling stand of plural stands at the time of biting a material to be rolled, after a prescribed time. CONSTITUTION:When a sheet bar 9 is bitten by the work rolls 2a of the 1st rolling stand 1a, a load cell 10a detects it to output its signal to a valve control device 12. The device 12 starts a timer provided to its inside, for instance, to open a shut-off valve 6a after a previously set time. Accordingly the flow rate of cooling water to be sprayed 4a is controlled to a small flow rate by a throttle valve 5a till a prescribed time passes after biting the bar 9, and the flow rate is increased after that time by opening the valve 6a. Here, the flow rate of cooling water till the valve 6a is opened, is set to about a half of the flow rate after a standby time, and further the flow rate after the standby time is set to the flow rate required for stationary rolling. Further in the figure, 8 shows a cooling water tank and 7 shows a pump respectively. |
