Influence of intermediate roll shifting on strip shape in a CVC-6 tandem cold mill based on a 3D multi-stand FE model

Intermediate roll shifting (IRS) is widely used for improving the strip shape in the six-high tandem cold mill, but most related studies are limited to a single stand. To fill the knowledge gap, a three-dimensional (3D) multi-stand elastic-plastic finite element (FE) model was developed for a continuously variable crown (CVC)-6 tandem cold mill using data transfer, which was then validated by industrial experimental results. Based on this FE model, the effects of the IRS on the strip crown, strip flatness, loaded roll gap profile and contact normal stress between rolls at each stand were quantitatively analysed. The results show that from Stand 1 (S1) to Stand 5 (S5), the regulation ability of the IRS on the strip crown shows a decreasing trend, which depends on the strip plastic rigidity; in contrast, the regulation ability on the quadratic flatness experiences an obvious increase from S1 to Stand 4 (S4), then a drop at S5, while the IRS exerts little effect on the quartic flatness and quartic crown of the loaded roll gap. Moreover, the most uniform distribution of contact normal stress emerges at different IRSs from S1 to S5. These findings can contribute to a better understanding of the role of the IRS in controlling the strip shape during tandem cold rolling (TCR).