Effects of Inclination of Strip Entering into Roll-Bite on Warpage Behavior in Rolling

Rolling experiments were conducted to investigate strip warpage behavior after rolling where the strip was inclined before a roll-bite with the roller guide. Direction of the strip warpage was explained by the shape factor Γ (contact arc length / mean thickness). The relationship between inlet inclination and outlet warpage of the strip was divided into four typical categories, by the shape factor Γ; 1) Γ < 1.0; a positive relation, 2) 1.0 < Γ < 1.9; a negative relation, 3) 1.9 < Γ < 3.1; a positive relation and 4) 3.1 < Γ; a negative relation. In other words, the sign of the warpage changes at three times with increasing the shape factor Γ. These experimental results were predicted by the two-dimensional rigid plastic steady-state finite element analyses. The analyses numerically showed that shear bands are initiated at the entrance of the roll-bite with the shear stress field, and that the intensity and configuration of the shear bands determine strip warpage behavior.