Effect of Post-Weld Heat-Treatment on Residual Stress of 20G Steel Welded Joint

Surface residual stresses and micro-residual stresses in 20G steel welded joint before and after heat-treatment were studied by X-ray stress analyzer and electron backscattered diffractometer (EBSD), respectively. The results show that the surface residual stresses distributed symmetrically along the weld center and decreased with increasing distance from the weld center. The average residual stress of the joint after heat-treatment was lower by 7.21% than that before heat-treatment. After heat-treatment, the recrystallization of the grains occurred in the weld zone, heated affected zone and base metal of the welded joint, resulting in the refinement of the grains. The kernel average misorientation values decreased, and the micro-residual stresses were released and distributed evenly due to the recrystallization. However, the micro-residual stresses in the weld zone were still relatively high.