Benders were the only actuators for strip profile and flatness control on the finishing stands in the No.2 hot strip mill of China Steel Cooperation. The capacity of benders is 2000 kN/chock. To satisfy the requirement of strip crown and flatness, the products for rolling schedule were classified into different groups, such as carbon steels, stainless steels and high strength steels. For each group, series of specified initial crown of work rolls for the different finishing stands were designed to fulfill |he requirements mentioned above. After applying this strategy, there still was 30 percent of product not reaching the aim crown because the benders had insufficient capacity. That means the shape control ability of mill for the present product mix was deficient For improvement, a trumpet curve was designed for work roll profile. As the work rolls shift, the equivalent roll crown changes and provides an additional and effective actuator for strip profile and flatness control. Those work rolls with trumpet curve were used on the upstream stands. For a specifically extremely thin carbon steel cycle, the percentage of aim product crown within + -10 mu m was significantly increased from 69 percent to 78 percent.
展开▼
