H_2S/CO_2环境中L360钢点蚀行为研究

Pitting Corrosion of L360 Steel in H_2S/CO_2 Environment

利用静态挂片失重法研究了含H_2S/CO_2模拟油田水溶液中,温度及Cl^-浓度对L360管线钢点蚀的影响,并利用Gumbel第一类近似函数分析了最深蚀孔概率.结果表明,在40℃～70℃之间,Cl^-浓度为10g/L条件下,点蚀的严重程度随温度增高而增大.恒定温度下.Cl^-浓度对点蚀发生也有明显的影响,当Cl^-在10～15 g/L范围时,腐蚀试样发生明显的点蚀;当Cl^-浓度大于20 g/L时,试样主要发生均匀腐蚀,随着Cl^-浓度的增大,腐蚀产物膜变僻更加疏松,保护性能下降,均匀腐蚀速率增大。最深点蚀分布服从Gumbel第一类近似函数.

The effect of temperature and Cl^- concentration on pitting corrosion of L360 steel in H2S/CO2 environment has been studied using methods of mass loss testing, SEM and XRD. The depth distribution of pits was analyzed with Gumbel first approximating function. The results showed that pitting corrosion tended to be more serious with the increase of temperature （from 40 ℃ to 70 ℃） in 10 g/L Cl^- solution. Pitting corrosion occurred in Cl^- solution with the concentration of 10-15 g/L at constant temperature, and uniform corrosion ccurred when the Cl^- concentration was higher than 20 g/L. As the temperature increased, corrosion products on the surface became looser and the protective property decreased. The measured maximum depth of pits followed the Gumbel first approximating function.