Springback behaviors of high strength stainless steel tube after numerical control rotary draw bending

Abstract

Taking the 21-6-9 (0Cr21Ni6Mn9N) high strength stainless steel tube (HSSST) of 15.88 mm × 0.84mm (diameter D × wall thickness t) as the objective, a three dimensional (3D) elastic plastic finite element (FE) model of the whole process of the 21-6-9 HSSST in numerical control (NC) rotary draw bending was established based on ABAQUS explicit/implicit code, and its reliability was validated. Then, the effects of process parameters on springback of the 21-6-9 HSSST in NC rotary draw bending were studied using the FE simulation based on orthogonal test. The results show that the effects of process parameters on springback angle and radius form high to low are the clearance between tube and wiper die Cw, mandrel extension length e, clearance between tube and mandrel Cm, friction coefficient between tube and wiper die fw, clearance between tube and pressure die Cp, friction coefficient between tube and bending die fb, friction coefficient between tube and pressure die fp, friction coefficient between tube and mandrel fm, clearance between tube and bending die Cb, bending speed ω, push assistant speed of pressure die Vp and e, Cw, Cm, fb, fw, Cb, fm, ω, Cp, fp, Vp, respectively. Springback angle and radius decrease with the increase of Cw, e or decrease of Cm, fb, fw, fm, Cb, while the Cp, fb, Vp and ω have no obvious influence on springback.