CVC cyclical shifting mode and its working characteristics for the mills of CSP

The compact strip production (CSP) line has two different rolling schedules: rolling strips with same width or rolling strips with different widths alternately. However, the continuously variable crown (CVC) work rolls used in the CSP production line do suffer from non-uniform wear in conventional shifting mode. A cyclical shifting mode for CVC work rolls is developed to uniform the work roll wear and to improve the quality of strip cross section. In this shifting mode, the work rolls shift with fixed mode, while the changes of strip crown caused by shifting are compensated by the bending force. A mathematical model is introduced to explain the working characteristic of the CVC cyclical shifting mode. A 3D finite element model of roll stacks for 1800 mm CSP hot rolling mill is built to calculate the parameters in the mathematical model. The working principle for the CVC cyclical shifting mode is determined as well. The proposed shifting mode has been implemented in the 1800-mm CSP production line. The work roll wear is more uniform by using the new shifting mode. This has resulted in the rolling length increasing by 20 % and the consumption of work roll decreasing by 14 %.