X70管线钢在南海环境下的腐蚀行为研究

Corrosion Behavior of X70 Steel in South China Sea Environment

由于海底环境复杂,海底管线钢经常面临严重的腐蚀风险。通过动电位极化技术和交流阻抗技术,探究了静水压力、溶解氧质量浓度及硫酸盐还原菌(SRB)接种时间对X70管线钢在南海模拟溶液中的电化学腐蚀行为,并结合电子显微镜表征技术分析了腐蚀形貌,阐明了三种环境因素共存条件下对X70钢腐蚀行为的作用机制。结果表明,X70管线钢在接种SRB的实验环境中的自腐蚀电流密度是无菌时的2倍;在0~3.5 MPa的压力下,腐蚀程度先加剧后减缓;SRB和溶解氧共存时,氧的存在抑制兼性厌氧菌SRB的数量,从而起抑制腐蚀的作用。

Due to the complex submarine environment, submarine pipeline steel often faces serious corrosion risk. Through potentiodynamic polarization technology and AC impedance technology, the effects of hydrostatic pressure, mass concentration of dissolved oxygen and growth days of sulfate reducing bacteria(SRB) on the electrochemical corrosion behavior of X70 pipeline steel in simulated solution in the South China Sea were investigated. Combined with electron microscope characterization technology, the corrosion morphology was analyzed, and the mechanism of the corrosion behavior of X70 steel under the coexistence of three environmental factors was clarified. The results show that the self corrosion current density of X70 pipeline steel in the experimental environment inoculated with SRB is twice that of sterile steel;under the pressure of 0~3.5 MPa, the corrosion degree first intensifies and then slows down;when SRB and dissolved oxygen coexist, the presence of oxygen inhibits the number of facultative anaerobic bacteria SRB, thus inhibiting corrosion.