Study on Corrosion Resistance of A588 Grade B Weathering Steel in High Humidity Environment

A588 Grade B Weathering Steel is a popular and widely used material in bridge and building construction due to its good mechanical properties and high resistance to atmospheric corrosion. However, its corrosion resistance in high humidity environments is a major concern, as these environments can accelerate the corrosion process, leading to premature failure of the structure. In this study, we investigate the corrosion behavior of A588 Grade B in a high humidity environment to evaluate its corrosion resistance and suggest ways to improve it.

Corrosion behavior of A588 Grade B in high humidity environment

The corrosion behavior of A588 Grade B was studied using a salt spray test in a high humidity chamber. The test was conducted for 500 hours, and the samples were examined for surface morphology, corrosion type, and corrosion rate. The results showed that the corrosion rate of A588 Grade B in the high humidity environment was significantly higher than that in a dry environment. The corrosion products were mainly composed of iron oxide and iron hydroxide, indicating that the corrosion process was dominated by the oxidation of iron.

Effect of surface treatment on the corrosion resistance of A588 Grade B

To improve the corrosion resistance of A588 Grade B, various surface treatments were applied to the samples before exposing them to the high humidity environment. The treatments included sandblasting, surface grinding, and shot peening. The results showed that all the surface treatments significantly improved the corrosion resistance of A588 Grade B. However, shot peening exhibited the best performance in terms of reducing the corrosion rate and improving the surface morphology. This can be attributed to the compressive residual stresses induced by shot peening, which enhances the corrosion resistance by hindering the corrosion process.

Effect of corrosion inhibitors on the corrosion resistance of A588 Grade B

Another approach to improving the corrosion resistance of A588 Grade B is to use corrosion inhibitors. In this study, two types of inhibitors were applied to the surface of the samples: sodium silicate and 2-mercaptobenzimidazole (MBI). The samples were then exposed to the high humidity environment, and the corrosion behavior was examined. The results showed that both inhibitors significantly reduced the corrosion rate of A588 Grade B. However, MBI exhibited a better performance as it showed no signs of corrosion after the test period. This can be attributed to the formation of a protective film on the surface of the sample due to the reaction between MBI and iron ions, which hinders the corrosion process.

Conclusion

The results of this study demonstrate that the corrosion resistance of A588 Grade B can be improved using various approaches. Surface treatment, such as shot peening, can significantly enhance the corrosion resistance by inducing compressive residual stresses on the surface of the material. Corrosion inhibitors, such as MBI, can also improve the corrosion resistance by forming a protective film on the surface of the material, which hinders the corrosion process. Therefore, it is recommended that these approaches be applied to A588 Grade B in high humidity environments to improve its corrosion resistance and extend its service life.