Modeling, prediction and validation of residual stresses and distortion in 2.25Cr-1Mo steel weld joints

In the present study, tungsten inert gas (TIG), and activated tungsten inert gas (A-TIG) welding processes were used for the preparation of 2.25Cr-1Mo (P22) steel weldments. The thermal cycles, residual stresses and distortion is simulated using SYSWELD software. The model predictions are validated using experimental tools. Finite element method based 3D meshed model is used to simulate the influence of welding passes on the distribution of temperature, residual stress and distortion. The simulated results are compared with the experimental results. Microstructure observations showed phase changes from ferrite to bainite and phase changes are taken into account in the numerical analysis. The heat input fitting tool has been used to calibrate the heat source by matching the simulated weld bead with that of the actual weld bead. There was good agreement between the predicted and measured thermal cycles and weld bead profile. Higher magnitude of residual stresses and distortion in MP-TIG weld joint is attributed to more weld metal volume caused by more number of weld passes required to fill the V-groove. A-TIG weld joint exhibited reduced residual stresses and distortion compared to that of multipass TIG weld joints. There was good agreement between the predicted and measured residual stress and distortion values for both the weld joints. (author)