Research on the generation and control of high-order flatness during the controlling of titanium strip profile by the intermediate taper roll in a 20-high mill

The wide-width titanium strip cold rolling, as an efficient titanium material processing technology, has been widely concerned. During the cold rolling process, high-order flatness defects occur frequently, seriously restricting the improvement of titanium product quality. To analyze the mechanical deformation behavior of titanium strips during cold rolling, and explore the influence of entrance and exit profile index on the generation of high-order flatness defects. An integrated coupling rolling model of the roll system and the strip has been established based on the FEM method, and the accuracy of the model has been verified using on-site measured data. The research results show that when the taper or coning amount of the first intermediate roll increases, if the entrance profile index remains unchanged, the exit profile index will significantly decrease, and the high-order deflection deformation of the work roll axis will occur, ultimately leading to high-order flatness defects. When using the first intermediate taper roll to control the exit profile index, if the exit profile index remains unchanged, the entrance profile index increases by 10 μm, and the coning amount will increase by 8.3mm. Therefore, a plan based on the optimization of the entrance profile index has been proposed, which takes into account both the profile and the high-order flatness, to achieve a smaller coning amount to meet the exit profile index and decrease the risk of high-order flatness. The industrial test results show that after the implementation of the plan, the occurrence rate of high-order flatness decreased by an average of 34.42%.