Theoretical and experimental investigation of cold rolling of tri-layer strip

A mathematical model for cold rolling of symmetrical sandwich strip is proposed using the upper bound theorem to investigate the plastic deformation behavior of the strip at the roll gap. The velocity fields derived from the proposed upper bound model can satisfy automatically the volume constancy and the velocity boundary conditions within the roll gap. Effects of various rolling conditions such as the initial thickness and flow stress of each layer in the strip, total thickness reduction and the frictional condition between the strip and roll on the rolling power, rolling force, and thickness reduction of each layer are discussed. Furthermore, experiments on sandwich strip rolling are conducted by employing aluminum, mild steel, copper as the layers of the sandwich strips. It is found that all of theoretical predictions are in good agreement with the experimental measurements. Through the study, it becomes clear that the proposed analytical method is applicable for simulating the cold rolling process of the tri-layer strip and is able to offer a useful knowledge in manufacturing the sandwich sheets and strips.