Residual Stress Modelling in a Thick-Sectioned Electron Beam Weld

Abstract

Previous work presented residual stress measurements in an electron beam weld in a thick section ferritic forging [1]; this weld was also modelled using finite element analysis. Due to the tool used to model the heat source, the mesh density in the region of the weld was limited. This work improves on the previous work by using a DFLUX subroutine to provide a mesh-independent heat source input, allowing a better mesh in the region of the weld. The modelling was carried out in Abaqus[2] using the VFT[3] user material model to allow phase transformation effects to be included. This however does not include creep properties and so the as-welded stresses were seeded on to a model that used Abaqus built-in material properties in order to model the heat treatment. The results of this analysis have been compared with analyses run using just the VFT material model (with no creep) and using just the Abaqus properties (with no phase transformation) in order to investigate the sensitivity of the stresses predicted to the material model used. The results of all three analyses have also been compared to the results of the original analysis and with the deep hole drilling residual stress measurements.