Effect of Corrosion Environment on Mechanical Behavior of 5083/6005A Welded Joints

The corrosion fatigue behavior of welded joints is a critical concern in the transportation industry, which shortens their service life. In this paper, the corrosion damage of 5083/6005A welded joints exposed to different conditions (3.5% NaCl + 0.01 mol/L NaHSO[sub.3], 3.5% NaCl, 0.6 mol/L NaHSO[sub.3], and 3.5% NaCl + 0.01 mol/L NaHSO[sub.3]-75 MPa) was investigated by using tensile and fatigue tests, polarization curves, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The findings indicate that elongation and fatigue life were most adversely affected by exposure to 3.5% NaCl + 0.01 mol/L NaHSO[sub.3]-75 MPa. This was followed by the exposure to 3.5% NaCl + 0.01 mol/L NaHSO[sub.3], then 3.5% NaCl, with the mildest effects observed under 0.6 mol/L NaHSO[sub.3]. The corrosion mechanisms were elucidated and the corrosion model was established through the analysis of corrosion morphologies and corrosion products. The corrosion fatigue fracture model was developed by analyzing the fracture surfaces. These findings provide references for preventing the corrosion-fatigue fractures of 5083/6005A welded joints, extending their service life, and enhancing the operational safety and reliability of trains.