Prediction of Mechanical Property Degradation after Corrosion of Q355B Steel Plates with Open Hole Defects

This paper focuses on the mechanical properties of cold-formed Q355B steel plates with open hole defects after corrosion. In this study, 2-mm and 3-mm thick steel plates were used as specimens. Four sets of specimens with different types of openings and one set of unopened holes were designed. After 10 accelerated corrosion cycles, the specimens underwent monotonic tensile testing to assess their mechanical properties post-corrosion. The results indicate that the ductility of the unopened corrosion specimen decreases with the increase in corrosion rate, and the failure mode gradually transitions from ductile to brittle failure. For open-hole specimens with less than 30% corrosion, the failure characteristics do not change significantly with increasing corrosion. The fracture location remains at the initial open hole defect. The area enclosed by the stress–strain curve of the specimen decreases significantly as the degree of corrosion increases. Both the height (for tensile strength) and width (for ultimate strain) of the curve decrease significantly, and the yield plateau gradually shortens or may even disappear. Based on the test results, a mechanical degradation model for open-hole steel after corrosion was established. The results were then compared with those of other scholars. In addition, this paper proposes an equivalent intrinsic model based on the Hollomon model that is more suitable for corroding open-hole steels.