Investigation on forming-welding process chain for DC04 tube manufacturing using experiment and FEM simulation

A chained forming-welding process is to be investigated and analyzed using experimental verification and numerical simulation in which the material and mechanical properties are fully transferred between processes. The investigated part is in the form of a tube with dimension of 300mm (l)x20mm (OD)x1.5mm (t) made of a low carbon steel material DC04 commonly used for automotive parts and support structure. At first, a series of experiment using industrial U-/O-bending machine and fully automated robotic gas metal arc welding (GMAW) process on longitudinal slot were sequentially conducted and analyzed towards final geometrical change, macrostructure, and residual stress. Further, numerical simulation method using specialized FEM software Simufact.Forming and Simufact.Welding is developed to predict the major properties following the actual process parameters during experimental forming and welding process. Throughout the simulation of forming and welding process, additive isotropic hardening plasticity model based on von Mises yield criterion is selected with a wide range of operating temperature and Goldak's double-ellipsoid is defined as welding heat source model. Based on the analysis outcome, it can be concluded that coupled forming-welding process simulation can be suitably implemented to forecast major material and mechanical properties of tube manufacturing within accepted range of error under consideration of material history.