Finite element simulation for predicting temperature and residual stresses distribution developed in dissimilar welds of Monel 400 and AISI 309L

In this paper, heat source model was developed for predicting temperature gradients and residual stress developing in welds of combined base materials AISI 309 L and Monel 400. The heat flux of 20.6 W/mm(2), 28.9 W/mm(2), and 35.8 W/mm(2) were considered to perform the transient thermal analysis. A sequentially coupled transient thermo-mechanical analysis has been used to carry out numerical simulation with ANSYS 18.0 Workbench. Variation in the material properties with temperature was considered during FE preprocessing. The Poisson's ratio of Monel 400 and AISI 309 L metals was considered to remain same. Boundaries are subjected to conduction and convection loads. Radiation heat transfer is also considered in boundary conditions. The peak temperature and its distribution at different time locations were predicted from simulation results. Thermal stresses were predicted by performing structural analysis by taking thermal histories as inputs from thermal analysis. The thermal stress distribution was observed to be lower at welding current of 140 A and voltage of 14 V. The minimum longitudinal and transverse thermal stresses were observed as 282 MPa and 159 MPa respectively. Uniform and balanced thermal stresses were predicted in final pass welding simulation when compared to other two welding passes simulation.