Phase Transformation Effects on Weld Distortion and Residual Stress Predictions

Welding distortion and residual stress has remained one of the major challenges in manufacturing. Extensive experimental efforts have been made throughout the history of manufacturing to understand and control the welding distortion and residual stresses. Extensive work has also been reported in the past couple decades in using analytical and computational methods to predict and quantify the effect of distortion and residual stress during the welding process. Examples of industrial welding applications using computational methods which highlight the challenges and benefits of using analysis and simulation tools to improve the quality and reduce the time and cost of the welding process development and problem resolution are discussed in [1–3]. One issue with regard to computational weld modeling needing addressed is with regard to material modeling. Since material melts and re-solidifies during welding, the use of a proper ‘weld’ constitutive model is critical. In particular, one issue regarding weld constitutive models is the phase transformations which can be important in some materials during weld solidification. This paper addresses this issue and shows some examples where the phase transformation effect is of second order importance and discusses when it must be properly considered.