Effects of Process Parameters on Springback of High Strength 21-6-9 Tube Bending Considering Variation of Elastic Modulus

In order to improve forming quality of high strength 21-6-9 tube bending and achieve its precise bending forming, the springback behaviors of high strength 21-6-9 tube in rotary draw bending are investigated. Based on explicit/implicit finite element (FE) software of ABAQUS, the whole rotary draw bending FE model of high strength 21-6-9 tube considering variation of elastic modulus was established, and its reliability was verified. Then, the springback behaviors considering varied elastic modulus of high strength 21-6-9 tube in rotary draw bending under different process parameters were explored and compared that with constant elastic modulus. The results show that the variation tendencies of springback angle are similar with or without considering varied elastic modulus, but augments the value of springback angle with considering varied elastic modulus. Springback angle augments with the increase of the friction coefficient of tube versus mandrel, the friction coefficient of tube versus wiper die or with the decrease of the friction coefficient of tube versus pressure die, while the springback angle firstly declines and then augments with increasing the clearance of tube versus pressure die and the clearance of tube versus wiper die.