Rust Characteristics and Corrosion Resistance of Q235B steel and Cr-Bearing Weathering Steel in Wenchang Marine Atmosphere

The rust layer characteristics and corrosion resistance of Q235B steel and 3Cr steel exposed to Wenchang marine atmosphere were studied by techniques such as corrosion weight loss method, scanning electron microscopy (SEM), X-ray diffraction (XRD) and electron micro probe (EMPA). The results show that the corrosion depth of Q235B steel was greater than that of 3Cr steel. The corrosion depth of both steels increased with the extension of exposure time. When the atmospheric exposure time was 1.5 a, the relative corrosion rate of 3Cr steel decreased obviously. There were many cracks in the rust layer of Q235B steel, and the rust layer of 3Cr steel was dense and had good corrosion resistance. The enrichment of Cl in Q235B steel reduced the corrosion resistance of the material, while the alloying element Cr in 3Cr steel was enriched in the inner rust layer, and the Cl element was basically blocked in the outer rust layer, which improved the corrosion resistance of the material.