A Study on the Weatherability of Weathering Steel after Atmospheric Corrosion

The weatherability of a weathering steel W450QN was compared with a carbon steel Q345 after 5 years atmospheric corrosion. The results indicated that the corrosion resistance was better for W450QN than Q345 based on the corrosion rate. The characteristics of the rust layers indicated the rust layer on W450QN was denser and thicker than that of Q345. The rust layers were mainly composed of goethite (α-FeOOH) with a few of lepidocrocite (γ-FeOOH). W450QN had better weatherability attributed to the alloying elements of copper, chromium and phosphorus enriched in the rust layer.