Objectives The welding residual stress seriously affects the mechanical properties and fracture strength of welded structures, so it is necessary to accurately evaluate and reduce the stress.

Methods The welding residual stress and residual stress after annealing heat treatment of T-shaped joint with multipass welding of EH550 steel with thickness of 30mmwere measured by non-destructive X-ray diffraction method; The macroscopic metallography of the examined T-shaped joint was obtained by means of wire-cutting and corrosion polishing. Based on the macroscopic metallography of the examined T-shaped joint weld, the finite element mesh model was established in ANSYS, and the rolling stress of EH550 was taken as the initial state for transient welding thermo-elastic-plastic finite element analysis, and the predicted residual stress of examined T-shaped joint and measured results were compared. Later, based on welding FE computation, annealing heat treatment was computed with considering material creep, and the influence of heat treatment parameters on welding residual stress was examined.

Results The predicted residual stress after welding and annealing heat treatment is in good agreement with the measured data. After heat treatment, the extreme residual stress decreased from more than 500MPa to 105 MPa.

Conclusions The relevant research results can be used for the accurate evaluation and analysis of the welding residual stress of high strength steel plate and the formulation of the process of eliminating the residual stress by annealing heat treatment.