Identification of residual stress intensity and its variation with heat source moving time in AISI304 steel pipe weldment: a significant failure investigation for structural integrity

In order to prevent any potential setbacks in modern ultra-supercritical power plants, a numerical welding simulation was conducted on thin AISI304 steel plates and pipes. This simulation aimed to evaluate various factors such as transient temperature distribution, thermal cycle curves, residual stress states, and deformation in the welded pipe. The analysis employed a sequential couple method, incorporating the Element Birth and Death (EBD) technique to simulate the addition of filler metal. For the thermal analysis, a prescribed temperature was applied using DC3D8 element type for plates and DC3D20 for pipe weldment. Remarkably, the calculated temperature histories outside the weld pool closely matched numerical and experimental measurements found in the literature. The results exhibited an acceptable deviation for the AISI304 plate weldment. Initial measurements of residual stresses were focused on locations with high intensity. The maximum peaks were identified on the inside surface of the pipe weldment, revealing Tresca stresses of 434.76 MPa and von Mises stresses of 371.89 MPa at a distance of 1.05 mm from the weld centerline (WCL). Additionally, inside circumferential stresses were observed at 361.44 MPa Tresca and 311.67 MPa von Mises at a distance of 9.5 mm from the weld centerline at the specific moment when the weld torch was at \(\left\{ {{\text{t}} = {16}0\left( {\text{s}} \right)} \right\}\) $\left\{\text{t}=160\left(\text{s}\right)\right\}$ .