Sensitivity analysis for springback of QSTE700 high-strength steel rectangular welded tube to material parameters in rotary draw bending

Springback is a key factor affecting the bending quality of QSTE700 high-strength steel rectangular welded tubes. During the production of the welded tubes, cold bending and welding of the steel strip can cause fluctuations of material parameters in the corner and weld zone, and these parameters can significantly affect the springback of the welded tubes in rotary draw bending (RDB). Therefore, a Morris sensitivity analysis system was established based on finite element model considering variable elastic modulus and anisotropy. Based on the built sensitivity analysis system, the effect of material parameters on springback and the sensitivity of springback to these parameters have been obtained. The results show that the parameter combination including strength coefficient and hardening index of the corner (K-c and n(c)) has a more significant effect on the springback angle, and the parameter combination including n(c) has a more pronounced impact on the springback of cross-section deformation. However, the parameter combination including yield stress of the corner (sigma(sc)) has little effect on the springback angle and the springback of cross-section deformation.