Comparison of evolution laws of stress and strain fields in hot rolling of titanium alloy large rings with different sizes

Abstract

For hot rolling of titanium alloy large rings, evolution laws of stress and strain fields in rings with various sizes were explored and compared based on a reliable coupled thermo-mechanical three-dimensional (3D) finite element (FE) model. The results show that for forming processes of different rings, as γ ¯ (the equivalent distribution ratio of feed amount per revolution of a process) decreases, the final peak Mises stress may transfer from the biting point at the driver roll side to that at the idle roll side, and the final peak equivalent plastic strain may transfer from the outside surface to the inside surface; as L ¯ (the equivalent deformation zone length of a process) increases, the final peak Mises stress may appear in the middle layer. The final positions of peak Mises stress and equivalent plastic strain are the combined effects of the above two aspects. In the deformation zone of a deformed ring, the surface layers are in the 3D compressive stress state, while the middle layer is in the 1D compressive and 2D tensile stress state or 2D compressive and 1D tensile stress state; the whole ring is in the 1D compressive and 2D tensile strain state.