What Does Pipeline Corrosion Mean?
Pipeline corrosion is a natural deterioration and destruction of pipe material and essential properties due to electrochemical and other ingredient reactions of pipeline materials with their environment - on the inside as well as outside surfaces. Like any other naturally occurring hazard, a pipeline corrosion can result in a life threatening failure and expensive damage to the pipeline and related system.
The study of pipeline corrosion is geared toward the following:
- Prevention of life threatening failures
- Measurement of the deterioration process
- Understanding and controlling the causes of pipeline material deterioration
- Taking corrective action to prevent further deterioration
Corrosionpedia Explains Pipeline Corrosion
Pipeline corrosion occurs naturally, due to the gradual and continuous environmental attack on pipe materials. It can happen on inside as well as outside surfaces. Pipe materials affected by corrosion include metal and non-metal pipes, pipe joints, welds and surface coatings. An example of pipeline corrosion is metal rusting in the presence of moisture and oxygen, which results in the formation of oxide of the metal, such as iron.
Corrosion also can occur in non-metals, such as ceramics or polymers. Corrosion changes the structure, essential properties and chemical composition of the materials. For example, iron is converted to oxides of iron and as it becomes brittle, loses its strength and integrity. Thus, the corroded pipe loses essential properties, such as mechanical strength and permeability to liquids and gases. This is observed daily in rusted pipes and other structures. Rusting and other forms of corrosion drastically reduce the useful life of pipeline, resulting in heavy financial repair and replacement costs.
Environmental conditions that influence corrosion are soil chemistry (in the case of buried pipes), ambient humidity, proximity to salt water, turbulence, velocity and pressure, type of transported liquid or gas and stray current proximity, if any.
In most cases, corrosion as an electrochemical reaction begins with a causative environmental agent that sets up an anode and cathode. The corrosion cell is generated through electrolysis in the presence of electrolyte, oxygen cell or through galvanic action, in the event of dissimilar metals in contact. Knowing corrosion's causative agent helps determine the type of protection that must be devised