Variable thickness rolling of plates thick in the middle and thin on the sides

Abstract Rolled profile strips (RPS) are poorly understood. In our previous work, only the type of rolled profile strips that are thick in both sides and thin in the middle (TM-type RPS) with a small thickness ratio of 1:1.3 were obtained by integrating the bending-spreading rolling (BSR) and the flattening rolling (FR). According to the process characteristics, the new process can be called variable thickness rolling (VTR). In this paper, experiments were performed to obtain RPSs that are thick in the middle and thin in both sides (TS-type RPS) with a thickness ratio of 1:1.8. The comparison between the influences of U-shaped and S-shaped roll design on the rolling results is carried out and the influences of different roll design parameters on thickness distribution, thickness uniformity, and the shape of the workpiece are discussed. The comparisons of stress and strain state of BSR process among different types of RPSs are conducted, and the forming characteristics of them are analyzed. Tension and the position of the target thinned areas have great influences on the results. The experimental results prove that the VTR technology can be well applied to TM-type as well as TS-type RPS. Through this work, varied RPSs with a thickness ratio from 1:1.3 to 1:1.8 can be produced, which contributes significantly to tailored blanks and lightweight development. In addition, a 3D RPS sample has also been made.