Research on Welding Stresses During Phase Transformation

In this paper, the stresses variation during phase transformation and its influence on residual stresses in low-alloy steel are investigated by means of thermal elastic-plastic finite element analysis. Three models were adopted to analyze the stresses during phase transformation. It was found that the residual stresses were lower than expected due to the abrupt variation of expansion coefficient caused by the volume expansion of the metal with its microstructure changes. The more the expansion coefficients changed, the more the residual stresses decreased. Furthermore, the lower the phase transformation temperature, the greater were the effects of phase transformation on residual stresses.