Cl^-残留对热轧碳钢大气腐蚀行为的影响

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

采用周期喷雾腐蚀试验模拟大气腐蚀,研究了热轧生产用循环水在钢板表面形成的Cl-残留对其储存过程中锈蚀的影响,设定每循环周期湿润时间为4h,模拟了C3级别的大气环境腐蚀性。结果表明,Cl-残留强烈影响钢的腐蚀速率,腐蚀速率与Cl-含量在一定范围内符合指数关系,当Cl-含量在60mg/L左右时腐蚀速率出现峰值,这是由钢板表面液膜内Cl-含量和氧溶量共同影响导致;降低生产用水中Cl-含量能有效提高钢板储存期的耐蚀性能,当Cl-从120mg/L降至40mg/L,其耐蚀性能可以提高三倍。综合经济因素考虑,将生产用水中Cl-含量控制在40mg/L左右为宜。

The influence of residual CI 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 Cl 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 Cl content was 60 mg/L, which might be explained by the combined influence of the dissolved chloride ions, and the dissolved oxygen. Reducing Cl- 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/L to 40 mg/L, hot rolled steel exhibited three times capacity of corrosion resistance. For economic perspective, the Cl- content in industrial circulating water at about 40 mg/L would be advisable.