Steel pipeline anti-corrosion materials are divided into pipeline-themed anti-corrosion materials and their corresponding filling materials. The main anti-corrosion mainly includes petroleum asphalt, epoxy coal tar, anti-corrosion cold wrap, epoxy powder, PE coating, and PP coating.
Commonly used filling methods include petroleum asphalt filling, epoxy coal tar filling, anti-corrosion cold wrapping tape, epoxy powder filling, PE heat shrinkable material filling, and other methods. If the main body of the pipeline is a three-layer PE composite structure, the filling material is a three-layer PE heat-shrinkable filling material. The single-layer epoxy powder coating can be repaired in three ways: epoxy powder, primer + anti-corrosion cold wrap, and PE heat shrink. In addition: the most widely used anti-corrosion layers for steel pipelines in China include petroleum asphalt, PE jacket and PE foam jacket, epoxy coal tar, coal tar enamel, epoxy powder, three-layer composite structure, etc. Currently, the two most widely used anti-corrosion method of the pipeline is a three-layer PE composite structure and a single-layer powder epoxy.
Petroleum bitumen has a wide range of raw materials and low prices. However, the working conditions are poor, the quality is difficult to guarantee, and the environmental pollution is serious.
Epoxy coal tar pitch is easy to operate, but the covering layer has a long curing time and is greatly affected by the environment. It is not suitable for field operations, and it is difficult to construct below 10 °C.
Anti-corrosion cold-wound tape, easy to operate, suitable for on-site construction, high waterproof performance, good strength, and not affected by the environment.
Epoxy powder anti-corrosion, an electrostatic spraying method, good fusion with the same material anti-corrosion pipe body, and strong adhesion, but epoxy powder has a poor waterproof (high water absorption, up to 0.83%), designed for cathodic protection brings certain difficulties. On-site equipment has high requirements, is difficult to operate, and the quality is not easy to control.
3PE heat-shrinkable material, strong anti-corrosion sealing, high mechanical strength, strong waterproof, stable quality, convenient construction, good applicability, and no pollution to the environment. PE has low water absorption (less than 0.01%), high epoxy strength, low water absorption of PE, the good softness of hot melt adhesive, etc., and high anti-corrosion reliability. The disadvantage is: compared with the cost of other filling materials, costly.
The characteristics of anti-corrosion cold-wound tape and 3PE heat-shrinkable tape are: applicable to the main anti-corrosion layer pipeline of various materials, while other methods are suitable for the main anti-corrosion layer pipeline of the same or similar material. Secondly, with the development of some pipelines, they also need to be insulated during anti-corrosion. Oil is a very complex mixture, and it is easy to corrode pipelines. Anti-corrosion is necessary, but oil product pipelines also need to be insulated in the case of anti-corrosion. In the northeast and winter, Thermal expansion and cold contraction will freeze and crack the pipeline, affecting stable supply.
