SOME ASPECTS OF FRICTION AND ANISOTROPIC RATIOS ON THE WORK HARDENING BEHAVIOR IN THE UPSETTING TESTS

Metal upsetting is a primary mechanical working operation to reduce the cross-section of the billets, and there are few challenges that are to be solved. When the billets undergo severe plastic deformation, the friction prevailing at the die/billet interface causes differential strain hardening and anisotropy in the metallic billets. The current work focuses on the effect of friction and anisotropy on the strain hardening behavior and hardness. AA2014 cast alloy were machined to an outer diameter of 24 mm, and an inner diameter of 12 mm with a thickness of 8 mm. Friction calibration curves were plotted from the ring compression test. Another set of solid cylindrical billets of the same composition with a height and diameter of 24 mm were compressed between the rigid dies. A distortion in the shape solid cylinders caused by friction, anisotropy, and their effect on strain hardening was studied after deformation. An equation was developed to predict he strain hardening behavior to investigate the effect anisotropy ratios on the strain hardening behavior. A novel approach to identify the effect of anisotropy ratios on the strain hardening behavior and hardness was proposed.