Investigation on fatigue performance of corroded butt weld of Q355NH weathering steel

作者：Qi Guo, Hongxiang Wang, Yan Lu, Ying Xing, Meijuan Gong, Fengxian Zhang · 发表于：Journal of Constructional Steel Research · 年份：2025 · DOI：10.1016/j.jcsr.2025.109894 · 被引用次数：5 · 研究领域：Hydrogen embrittlement and corrosion behaviors in metals、Welding Techniques and Residual Stresses、Fatigue and fracture mechanics

The application of uncoated weathering steel in bridge structures is on the rise. However, the corrosion fatigue of its welded joints poses a significant threat to structural integrity. This study focuses on the fatigue issues of Q355NH weathering steel and Q355 steel butt welds after corrosion. Based on neutral salt spray tests and macro-micro analyses, the morphology, composition and pit evolution patterns in different weld zones were quantitatively elucidated. The rust exfoliation mechanisms and failure mechanisms under cyclic loading were also revealed through fatigue tests. Additionally, S N curves and fatigue strengths for butt welds with different corrosion degrees were established. Results indicated that, the fatigue cracks initiated near the weld toe in the heat-affected zone (HAZ). Within the first 30 days of corrosion, Q355NH specimens ( η = 6.59 %) demonstrated superior fatigue performance compared to Q355 specimens ( η = 9.15 %). However, after 60 days ( η ≥ 13.32 %), the weathering steel specimens no longer exhibited enhanced fatigue resistance. Furthermore, a modified fatigue life prediction method was proposed and validated. The proposed method could effectively simulate fatigue life of corroded butt welds under different corrosion levels. These corrosion-fatigue behavior findings provide technical guidance for designing and maintaining weathering steel bridges.