Strength mismatch effect on residual stress of 10CrNi3MoV steel considering the back-chipping process

The paper investigates the Welding Residual Stresses (WRS) of 10CrNi3MoV high strength steel multipass butt welded joints by experimental measurement and numerical calculation considering the effects of weld metal strength mismatch and back-chipping processing. Firstly, a thermo-metallurgical-mechanical simulation model was developed incorporating the Effect of Solid-State Phase Transformation (SSPT) to obtain multipass welding residual stress distributions after the back-chipping processing for evenmatched filler material. 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. Then, the effects of weldment mismatch and back-chipping processing on WRS for the multipass welds were analyzed. Comparing the calculated residual stress results (with and without consideration of SSPT) with experimental data shows that more accurate WRS predictions are obtained when the SSPT effect is incorporated in the simulation procedure. For evenmatched welded joints, the compressive WRS were distributed in the top and back weld layer due to the involvement of SSPT behavior. While the considerable tensile WRS in undermatched weldments was obtained without considering the SSPT, the magnitudes were lower than those in Heat Affected Zone (HAZ). The proposed finite element model can predict the WRS of high-strength steel multipass welded joints and provide a theoretical basis for conducting the structural integrity assessment.