深远海勘探平台异形构件的腐蚀行为研究

    Research on Corrosion Behavior of Shaped Components of Deep Offshore Exploration Platforms

    • 摘要: 由于深远海勘探平台异形构件(地脚螺栓)长期暴露于复杂的海洋环境中,异形构件的表面和内部结构不断受到腐蚀作用的侵蚀,使其失去了原有的强度和稳定性,严重危及海上设施的安全运行。采用COMSOL多物理场耦合技术,研究分别在盐雾与干湿交替环境下力学与电化学的机电耦合效应对异形构件腐蚀行为的影响。通过实验测定Q345钢的力学性能和不同环境下的电化学腐蚀行为,将实验数据输入到仿真模型中。模拟结果表明,机电耦合效应下的异形构件腐蚀电位会比未受力状态更负,腐蚀电流密度也更高,更容易发生腐蚀失效。在同等力学作用下,干湿交替环境下腐蚀坑的面积大且数量多,腐蚀程度高于盐雾环境。地脚螺栓的易腐蚀位置主要在螺杆与弯头连接处。

       

      Abstract: As the shaped members(ground bolts) of deep-sea exploration platforms are exposed to complex marine environment for a long time, the surface and internal structure of the shaped members are constantly eroded under the corrosive effect, which loses their original strength and stability, and seriously endangers the safe operation of offshore facilities. COMSOL multi-physical field coupling technology was adopted to study the influence of mechanical and electrochemical coupling effect on the corrosion behavior of shaped members under the salt spray, dry and wet alternating environments, respectively. The mechanical properties and the electrochemical corrosion behavior of Q345 steel under different environments were determined experimentally, and the experimental data were input into the simulation model. The simulation results show that the corrosion potential of the shaped members under the electromechanical coupling effect is more negative than that of the unstressed state, and the corrosion current density is higher, which makes them more prone to corrosion failure. Under the same mechanical effect, the area and number of corrosion pits in the dry and wet alternating environment are large and the degree of corrosion is higher than that in the salt spray environment. The corrosion-prone position of the ground bolt is mainly located at the connection between screw and elbow.

       

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