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

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.