High-cycle fatigue performance evaluation of corroded typical Q690D welded details

This is the authors' abstract. We don't add key points for this paper.

Existing studies on the fatigue performance of welded details have predominantly focused on non-corroded conventional-strength steel, whereas fatigue data for high-strength steel under corrosive conditions remain limited. This study therefore investigates the effect of corrosion on the fatigue performance of Q690D welded details. High-cycle fatigue tests were conducted on butt welds (BW) and cruciform load-carrying fillet welds (CFLW) at four corrosion levels, and the effects of uniform and localized corrosion were examined through experimental and numerical analyses. The pitting factor K p was determined from high-resolution scanned surface profiles, and its correlation with surface roughness parameters was established. The results show that the fatigue performance of non-corroded and pre-corroded BW can be evaluated using fatigue strength categories (FAT) 90 and 80, respectively, and that of non-corroded and pre-corroded CFLW can be evaluated using FAT 71 and 63, respectively. Stress concentration analysis reveals that representing corroded surfaces using regular geometries is unconservative. For base metal, fatigue resistance is governed by localized corrosion-induced stress concentrations, which can be evaluated by considering both the reduction in effective cross-sectional area and K p . For welded details, fatigue behaviour is governed by the more critical stress concentration associated with either corrosion pits or the inherent geometric notch of the welded detail. This research enriches the fatigue database for high-strength steel welded structures and provides an experimental foundation for the durability assessment of steel structures in corrosive environments.