Effects of salt spray corrosion on low cycle fatigue properties of a ferrite-bainite weathering steel

• Published in: Corrosion science 2025-02, Vol.243, p.112578, Article 112578
• Main Authors: Du, Yaohan, Liu, Hanqing, Li, Xue, Liu, Yongjie, Liu, Fulin, He, Chao, Yang, Kun, Yang, Ying, Wang, Qingyuan
• Format: Article
• Language: English
• Subjects: Corrosion pits; Crack initiation; Ferrite-bainite weathering steels; Low cycle fatigue; Strength degradation
• ISSN: 0010-938X
• DOI: 10.1016/j.corsci.2024.112578

Corrosion pits preferentially initiate in the bainitic regions of Q420qNH steel against the simulated marine atmospheric environment, where a high initial dislocation density is present. This occurs in addition to the initiation sites associated with nonmetallic inclusions that exhibit significant lattice distortion. The formation of corrosion the corrosion-induced non elastic buckling exacerbates the cyclic softening effect and significantly reduces fatigue strength. At a strain amplitude of 0.4 %, the fatigue life decreases by 73.2 % after 60 days of pre-corrosion treatment. Layered segregation of Cr and Cu alloying elements could develop the formation of dense rust layer to inhibit further surface degradation. •Corrosion pits of ferrite-bainite weathering steel predominantly occur in the bainite regions with high initial dislocation density upon cyclic salt spray corrosion environment.•Hierarchical non-metallic inclusions enclosed by a significantly distorted lattice shell tend to be preferential initiation sites for corrosion.•Surface degradation caused by corrosion pits, coupled with the cyclic softening, could result in inelastic buckling upon low cycle fatigue loading, leading to fatigue strength degradation.