Reduction of flatness defects in thin metal sheets by a pure tension leveler

In metal industries (aluminum, steel,…), the flatness defects of the thin strips can be corrected by pure tension leveling. This process is able to minimize the residual stresses from rolling step by plastically lengthening the metal sheet. This paper introduces a numerical modeling of strip conveying through a simplified industrial leveler (composed of four rolls), using a commercial FEM software. It includes shell elements discretization and frictional contact between strip and rolls. From plastic strains and residual stresses through width and thickness, the final strip shape is predicted. The Finite Element model shows how an entering strip with a flatness defect (manifested or latent) is transformed at the leveler exit: waves are decreased and longitudinal stresses gap is reduced.