FEM prediction of welding residual stress and distortion in carbon steel considering phase transformation effects

The objective of this study is to investigate the effects of solid-state phase transformation on welding residual stress and distortion in low carbon and medium carbon steels. In this study, based on ABAQUS code, a sequentially coupled thermal, metallurgical, mechanical 3-D finite element model is developed. In the numerical simulations, different continuous cooling transformation diagrams are used to predict the fractions of martensite for the fusion zone, the coarse-grained HAZ and the fine-grained HAZ, respectively. Effects of volume change due to austenite–martensite transformation on the final residual stress and the welding distortion are examined. The simulation results revealed that the final residual stress and the welding distortion in low carbon steel do not seem to be influenced by the solid-state phase transformation. However, for the medium carbon steel, the final residual stresses and the welding distortion seem to be significantly affected by the martensitic transformation.