Strength mismatch effect on residual stress of high strength steel butt-welded joints

This study was mainly concerned with the residual stresses of 10CrNi3MoV high strength steel multipass butt welded joints by experimental measurement and numerical calculation considering the weld metal strength mismatch effect. Firstly, the Solid-State Phase Transformation (SSPT) processing of weldment was described by the thermo-metallurgical-mechanical simulation model. The residual stress distribution on the basis of the established procedure. Phase transformation modeling of diffusionless transformation kinetics based on the Koistinen-Marburger formula was performed by a user subroutine implemented in ABAQUS. Additionally, strain transformation calculation due to volumetric and heating change during the SSPT was completed by the user-defined subroutine. The results show that more accurate predictions of welding residual stress are obtained when the SSPT effect is incorporated in the simulation procedure. For evenmatched welded joints, the compressive residual stresses were distributed in the top and back weld layer due to the involving of SSPT behavior. The proposed finite element model can predict residual stress of high strength steel multipass welded joints and provide a theoretical basis to conduct the structural integrity assessment.