Influence of Residual Cl on Corrosion Behavior of Hot Rolled Steel in Atmosphereic Envoronment

The influence of residual Cl on the corrosion behavior of hot rolled steel in atmospheric environment was studied by means of spray dry-wet corrosion test, which was applied to simulate atmospheric corrosion, C3-level of corrosive atmospheric environment was simulated with 4 hours wetting time in each corrosion cycle. The results showed that the atmospheric corrosion rate of hot rolled steel was greatly influenced by C content in industrial. circulating water, an exponential relationship between the corrosion rate and Cl content was exhibited in a certain range. The corrosion rate showed a peak when C content was 60 mg/L, which might be explained by the combined influence of the dissolved chloride ions, and the dissolved oxygen, Reducing C content in industrial circulating water would be an effective way to improve the surface quality of hot rolled steel. When Cl content reduced from 120 mg/ 1. to 40 mg/L, hot rolled steel exhibited three times capacity of corrosion resistance, For economic perspective, the C content in industrial circulating water at about 40 mg/I. would be advisable.