Effects of thermal transport in computation of welding residual stress and distortion

Abstract

The effects of considering thermal transport in weld modelling of residual stress and distortion are evaluated by performing a thermal transport analysis first to compute the temperature history which is then used as loading in a conventional elastoplastic analysis to compute the residual stress. A gas metal arc welding (GMAW) and a hybrid GMAW/laser welding case are used as examples. For each weld, residual stresses are computed once assuming conductive heat transfer only and once assuming convective (thermal transport) heat transfer. For GMAW welding, both heat conduction and thermal transport analyses produced similar temperature, residual stress and distortion results, indicating that heat conduction modelling with the double ellipsoid model may be sufficient for modelling GMAW. For hybrid welding, the heat conduction and thermal transport analyses produced different temperature histories and distortion results, demonstrating the need for including thermal transport effects in modelling keyhole welding. However, the residual stress results were in close agreement, suggesting that heat conduction analyses may be sufficiently accurate for computing residual stress even in keyhole welding.