Signifcant springback occurs after tube rotary-draw-bending(RDB),especially for a high-strength Ti–3Al–2.5V tube(HSTT) due to its high ratio of yield strength to Young's modulus.The combination scheme of explicit and implicit is preferred to predict the springback.This simulation strategy includes several numerical parameters,such as element type,number of elements through thickness(NEL),element size,etc.However,the influences of these parameters on springback prediction accuracy are not fully understood.Thus,taking the geometrical specifcation9.525 mm · 0.508 mm of a HSTT as the objective,the effects of numerical parameters on prediction accuracy and computation effciency of springback simulation of HSTT RDB are investigated.The simulated springback results are compared with experimental ones.The main results are:(1) solid and continuum-shell elements predict the experimental results well;(2) for C3D8R elements,NEL of at least 3 is required to obtain reliable results and a relative error of 29% can occur as NEL is varied in the range of 1–3;(3) specifying damping factor typically works well in Abaqus/Emplicit simulation of springback and the springback results are sensitive to the magnitude of damping factor.In addition,the explanations of the effect rules are given and a guideline is added.
How to control the microstructure of titanium alloy bars is important to fabricating high-performance aerial forgings. This paper gives a thorough survey of the manufacturing methods and microstructure control techniques for titanium alloy bars. It summarizes the effects of processing parameters on the mechanisms and laws of microstructure evolution during b working and(a + b) working, including the kinetics and grains size of dynamic recrystallization(DRX) during b deformation and the kinetics and grains size of spheroidization during(a + b) deformation. The trends in microstructure control techniques are presented for fabricating titanium alloy bars with high efficiency, low cost, and high quality by means of b/(a + b) working, and the puzzles and challenges in the future are also pointed out.
