3D-FE study on deformation behaviors in cold pilgering of high strength TA18 titanium alloy tube

Regarding stress/strain changing tendencies and material flow trajectories, the deformation behaviors of high strength TA18 titanium alloy tube in whole tube cold pilgering are numerically studied. Under ABAQUS/Explicit platform, 3D elastic-plastic FE model is established and validated by the law of energy conservation. Key modeling technologies are solved, such as geometry definition of variable cross-section rollers and parabola-shape mandrel, coordinate movement of tools and elimination of excessively distorted meshes. The main results show that: 1) During the whole process, 3D stresses fluctuate between tension and compression. In the instantaneous deformation zone, radial stress keeps constant along thickness. In the roller flange area, hoop and axial stresses on inner surface are larger than which on outside surface, while opposite in the roller groove bottom. (2) During the whole tube cold pilgering, Compressive radial and hoop strains decrease while tensile axial strain increases. In the instantaneous deformation zone, hoop strain keeps constant along thickness, while radial and axial strains on inner surface are slightly larger than which on outside surface. 3) With preform tube deformed into final tube, tube materials move forward along the helix trajectories, and it can be concluded that tube elongation increases linearly.