Influence of transverse property differences in hot-rolled high-strength strip on cold rolling deformation behavior

In recent years, the widespread application of high-strength strips in industries such as automotive manufacturing and household appliances has imposed increasingly stringent requirements on dimensional accuracy, while also heightening the sensitivity to variations in the raw material properties during cold rolling. The presence of transverse property differences (TPD) in hot-rolled high-strength strips has been found to significantly undermine the quality stability of cold-rolled products. To address this issue, a simulation of transverse performance variability during rolling was carried out based on the finite element method. The simulation results showed that the relative errors between the calculated rolling force, the central thickness of the strip, and the measured values were controlled within +/- 6% and +/- 0.25%, respectively. Further analysis revealed that when the transverse yield strength fluctuated between 425 and 570 MPa, the corresponding rolling pressure exhibited a consistent wavy distribution, resulting in localized deformation non-uniformity. These differences led to the formation of "local wave" on the surface, particularly in regions with abrupt yield strength changes exceeding 30 MPa over 50 mm. Additionally, by comparing rolling conditions with and without property homogenization, it was observed that the thickness calculation error could reach up to 15 mu m, indicating a significant improvement in strip shape. Finally, the effects of reduction rate, roll bending, and roll shifting on the shape evolution of the strip with transverse property variation are described and discussed.