Strip Warpage Behavior and Mechanism in Single Roll Driven Rolling

Curling of Sheet in Asymmetric Rolling Investigated by Profile Measurement of Partly Rolled Sheet

“…In (1), the curling directions were downward at r ≤ 18%. With reduction r ≥ 28%, the curling direction changed to upward, which was same with the conclusions by Kasai et al 10) and Nikkuni et al 11) It is easily deduced that reduction in thickness has an effect on curling direction under differential-speed rolling.…”

“…They reported that the sheet curls to the slower roll side with low shape factor, while curls to the faster roll side with high shape factor. After them, several researchers such as Minton et al, 5) Pawelski, 9) Kasai et al 10) and Nikkuni et al 11) confirmed the finding and used the shape factor to explain the curling direction.…”

“…On the other hand, at higher reduction r > 28%, L L /L U > 1 is because that the sheet speed of the lower surface is faster, which can be explained by that the shear bands reflected on the upper faster roll surface. 10,11) The shear bands promote the sheet speed on the lower surface and the neutral point on the lower roll surface is more displaced than the upper surface so that the L L is longer than the L U .…”

“…Based on finite element analysis (FEA) of asymmetric rolling, Pawelski 9) reported the arrangement of shear bands depends on the shape factor. Then, Kasai et al 10) and Nikkuni et al 11) explained the changing of curling direction by shear bands. They supposed that with low shape factor, a pair of shear bands is produced at the entrance of the roll-bite on the surfaces of the sheet, propagating along the inclined directions with 45° to the rolling direction.…”

Microstructure and Texture Evolution with Relation to Mechanical Properties of Compared Symmetrically and Asymmetrically Cold Rolled Aluminum Alloy

“…This can involve rolling with different roller diameters, rolling with the uneven use of lubricants, rolling with single-drive roller and rolling with different rotation speeds of the rollers. The latter two are more appropriate for rolling mills in the industry [12][13][14][15][16][17]. Rolling with different rotation speeds, where the so-called "grabbing problems" are less significant than with a single-drive roller, have an impact on changes to the workpiece's thickness as a consequence of the uneven distribution of the longitudinal velocity.…”