Investigation of rolling deformation oscillations and the bending mechanism in asymmetric rolling

The bending mechanism of asymmetrically rolled plates remains insufficiently understood, particularly regarding the deformation behavior induced by stress oscillations during rolling. In this study, finite element simulations were integrated with an asymptotic analytical approach to elucidate the oscillatory characteristics of the plastic strain rate along both the rolling and thickness directions. The analysis clarified the evolution of stress and strain responses during rolling and revealed the bending behavior of asymmetrically rolled plates. Rolling experiments were conducted to verify the accuracy of the simulation results. The results indicate that increasing the speed ratio leads to significant restructuring of the rolling pressure. At a lower reduction ratio, this redistribution extends the X a strain-rate band formed near the neutral point toward the slow roll exit, resulting in more severe surface deformation at the exit and ultimately inducing plate bending toward the fast roll side. Increasing the reduction ratio weakens the asynchronous effect and increases the number of plastic strain-rate oscillations within the deformation zone. Constrained by the rolls, the X a strain-rate band variant influences the newly formed X b strain-rate band before exiting the rolls, causing this band to widen on the upper surface and disappear on the lower surface, ultimately resulting in the plate bending toward the slow-roll side. The elucidation of oscillatory behavior of strain-rate bands and clarification of the mechanism by which rolling parameters affect plate bending provide valuable theoretical insights for the prediction and control of bending behavior in asymmetric rolling.