Springback law of thin-walled 6061-T4 Al-alloy tube upon bending

To achieve the precision bending deformation, the springback behaviors under various forming conditions should be clarified preliminarily. Taking the thin-walled 6061-T4 Al-alloy tube of 50.8 mm×0.889 mm (outer diameter×wall thickness) as the objective, the single-factor experimental analysis and the 3D-FE based numerical orthogonal test are conducted to address the effects of forming parameters on the springback behaviors in 6061-T4 Al-alloy tube bending. The results show that: 1) The springback angle increases linearly with increasing of the bending angle. 2) The significant factors from high to low are the clearance between tube and mandrel, the bending radius, the friction between tube and pressure die, the clearance between tube and wiper die, the clearance between tube and pressure die, the coefficient of boost velocity, the friction between tube and mandrel, the number of mandrel balls. 3) The effect rules of significant parameters on springback of 6061-T4 Al-alloy tube are similar to those of stainless steel and Ti-alloy tubes. Springback becomes larger with increasing of the bending velocity, the tube-die clearance, the relative bending radius, the tube-pressure die friction and relative push assistant speed. While the springback decreases with increasing of the mandrel extension length, the number of mandrel balls and tube-mandrel friction.