Stress-strain analysis of NC bending and springback process for 21-6-9 stainless steel tube

Abstract

In order to study the distribution of stress-strain of bending and springback process, based on the platform of ABAQUS code, a 3D elastic plastic model of the whole NC bending process of 21-6-9 (0Cr21Ni6Mn9N) stainless steel tube was established, and its reliability was validated. Then, the distribution and variation laws of the stress-strain for bent tube during NC bending and springback process were obtained by FE simulation. The results show that the outside of bent tube suffers tangential tension stress, and that of the inner is more complicated after bending. The stress unloading is not obvious after retracting mandrel, which indicates that the process of retracting mandrel has less effect on springback. The stress unloading is obvious, and a reverse loading phenomenon occurs after springback, while the strain of the bent tube is nearly not changed. The results can provide theoretical basis for springback control during tube NC bending process.