| 摘要 |
PURPOSE:To reduce center segregation of a cast slab and to improve quality by dividing multiple pairs of rolls executing light rolling reduction to the non-solidified cast slab, measuring rolling reaction received from the cast slab and adjusting the roll reduction rate and cooling water injection rate, so as to come to the specific strain speed by grasping the strain speed of the cast slab. CONSTITUTION:At the time of applying the light rolling reduction at suitable strain speed to the cast slab 30 at the end time of solidification, the reaction (b) is acted to the divided roll 16b. The roll 16b is pushed by the cast slab 30 and detecting part of a measuring instrument 39b is deformed and the resistant value of the detecting part is changed, to generate current. This current is converted into voltage signal and inputted to a storing part of CPU40 and based on the input data of the reaction (b), the strain speed of the cast slab is calculated as a parameter. Then, the parameter is compared with the prescribed suitable strain speed and the difference is transmitted to a hydraulic control device 42 as the voltage signal. Then, the different signal is transmitted to a cooling water control device 44, too, to adjust the spray water rate injected to the divided roll 16b, so that the different signal comes to zero. Further, the reducing the rolling reduction rate of the roll 16b, the reaction (b) is relaxed, and by making the strain speed of the cast slab 30 at the suitable speed, flowing of the molten steel in the internal part of the cast slab 30 is prevented and the center segregation is reduced. |
