Fatigue life prediction for corroded butt welds made of 1.4301 stainless steel and Q460 high-strength steel: Numerical analysis and new design rules

In a corrosive environment, the weld is highly susceptible to both corrosion and fatigue. This exposure can lead to the initiation of fatigue cracks and even result in the complete failure of structures. However, no established design guidelines were available for predicting the fatigue life of corroded butt welds made of 1.4301 stainless steel and Q460 high-strength steel. To address this, this study presents an extensive numerical analysis to develop a new fatigue life prediction model for corroded 1.4301 stainless steel and Q460 high-strength steel with transverse and longitudinal butt welds. Finite element (FE) models incorporating the material non-linearity and initial geometric imperfections obtained from the 3D scanning were developed and the accuracy of FE models was verified against the corresponding experimental findings. A detailed parametric study was subsequently undertaken using the validated FE models, and a total of 128 FE results were generated. Variables which were examined included the mass loss rate and the corrosion rate. The parametric study findings indicated that the fatigue life of corroded welds was significantly influenced by the mass loss rate. Finally, new prediction models for determining the fatigue life of corroded butt welds were proposed, which can establish the relationship between the mass loss rate and the fatigue life. The newly proposed prediction model can closely predict the fatigue life of corroded welds made of two materials.