Corrosion is one of the most damaging factors in offshore structures that can lead to significant damage and even catastrophic structural failure. Corrosion control is vital for the long-term success of offshore oil rigs and other structures like offshore wind structures.
Welds produced in offshore environments are usually more susceptible to corrosion than the base metal. So, weld corrosion control requires additional consideration because more variables are involved.
What Is Corrosion And Why It’s So Prevalent In Offshore Environments
Corrosion is a natural, chemical process during which metals erode. The refined metals are converted into more stable compounds, like metal oxides, via the action of environmental moisture and oxygen. This is a spontaneous process that is very challenging to prevent.
Water works like an electrolyte to facilitate the ion path, while the metal transfers its electrons from the anodic area to the cathodic area. So, you can think of the corrosion process like a battery, but instead of energy, the end product is corrosion and material erosion. In the presence of moisture, water, and sea chlorides, metals erode by transferring electrons from an anodic area (+) to a cathodic area (-). As a result, the anodic area loses material mass as it dissolves.
The seawater contains salts, like sodium chloride, which drastically exacerbate the corrosion process, which is why offshore structures are at a significant risk of corrosion-related structural failure. (more…)