What materials can be used for steel pipeline anti-corrosion layers

The most commonly used steel pipeline anti-corrosion layers in China include petroleum asphalt, PE jackets, PE foam jackets, epoxy coal tar, coal tar enamel, epoxy powder, three-layer composite structure, epoxy coal tar cold wrap (PF type), rubber-plastic epoxy coal tar cold wrap (RPC type), etc. At present, the most widely used pipeline anti-corrosion methods are three-layer PE composite structure, single-layer powder epoxy, PF-type cold wrap, and RPC-type cold wrap.

Petroleum asphalt 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 is easy to operate, but the coating has a long curing time, is greatly affected by the environment, is not suitable for field operations, and is difficult to construct below 10°C.

Epoxy powder anti-corrosion adopts the electrostatic spraying method, which has good fusion with the pipe body of the same material anti-corrosion and strong adhesion, but epoxy powder has poor waterproofness (high water absorption rate, reaching 0.83%), which brings certain difficulties to cathodic protection design. The requirements for on-site equipment are high, the operation is difficult, and the quality is not easy to control.

3PE heat shrinkable material has strong pipeline anti-corrosion sealing, high mechanical strength, strong waterproofness, stable quality, convenient construction, good applicability, and no pollution to the environment. PE has low water absorption (less than 0.01%), and at the same time has high epoxy strength, low PE water absorption good softness of hot melt adhesive, etc., with high anti-corrosion reliability. The disadvantage is that the cost is high compared with the cost of other patching materials.

PF-type and RPC-type cold wrapping tape are easy to construct. The three matching setting glues make PF-type epoxy coal tar cold wrapping tape that can be constructed in any environment, any season, and any temperature conditions.

The characteristics of cold wrapping tape and 3PE heat shrinkable tape are: suitable for pipelines with the main anti-corrosion layer of various materials, while other methods are suitable for pipelines with the main anti-corrosion layer of the same or similar materials.