Soil corrosion: When the pipeline is buried underground, the nature of the soil has an important influence on the corrosion of the pipeline. For example, differences in soil pH, salt content, water content, air permeability and other factors will form different corrosion environments. Acidic soil will directly corrode the metal of the pipeline; soil with high salt content will enhance the conductivity of the electrolyte solution and accelerate electrochemical corrosion; moist and poorly permeable soil will create an oxygen-deficient environment, promote the growth of anaerobic bacteria, and induce microbial corrosion.
Atmospheric corrosion: For the exposed parts of the pipeline on the ground, substances such as oxygen, water vapor, sulfur dioxide, and nitrogen oxides in the atmosphere will react chemically with the surface of the pipeline to form corrosion products such as rust. Especially in industrial pollution areas, coastal areas and other environments, the content of corrosive substances in the atmosphere is high, and the atmospheric corrosion problem of pipelines is more serious.
Stray current corrosion: When there are external power sources such as electric railways and high-voltage transmission lines around the pipeline, stray current may flow into the pipeline, making the pipeline an anode and causing electrochemical corrosion. Stray current corrosion is characterized by fast corrosion rate and strong locality, which can easily lead to serious consequences such as pipeline perforation.
Corrosion under insulation: In order to reduce heat loss, some pipelines will use insulation measures. However, if the insulation layer is damaged or water seeps in, a humid environment will form under the insulation layer, causing corrosion. This type of corrosion is usually difficult to detect, but once it occurs, it will develop rapidly and cause serious damage to the pipeline.
