Ultrasonic impact treatment (UIT) is widely employed as a post-weld treatment to enhance the fatigue performance of welded joints through the introduction of surface plastic deformation and compressive residual stresses. While its beneficial effect on fatigue life when applied at an earlier stage is well established, the influence of UIT on aged structures remains controversial in the literature. This study investigates the effect of UIT on the corrosion performance of S355 steel welded T-joints after accelerated corrosion-induced aging. As-welded (AW) and UIT-treated T-joints were subjected to salt spray exposure, followed by detailed microstructural and surface analyses to assess corrosion morphology and damage evolution. The results show that UIT induces significant surface plastic deformation and microstructural refinement in the weld toe region without promoting preferential corrosion aging or accelerated degradation. The aging behavior of UIT-treated joints, following accelerated environmental exposure, is comparable to that of the AW condition, with corrosion rates decreasing from 3.27 and 3.28 mm/year at 42 days to 1.32 and 1.26 mm/year at 126 days for AW and UIT specimens, respectively. These results indicate that the compressive residual stresses and surface modifications introduced by UIT do not adversely affect material durability. These findings clarify the role of UIT under such exposure conditions and demonstrate that UIT can be applied as a post-weld treatment to improve fatigue properties without compromising the long-term performance of structural steel welded joints.
Zouari et al. (2026) studied this question.