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4 h, 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60 mg/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120 mg/L降至40 mg/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40 mg/L左右为宜。

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 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.