What materials can be used for the anti-corrosion coating of steel pipes

In China, commonly used anti-corrosion coatings for steel pipes include petroleum asphalt, PE jackets and PE foam jackets, epoxy coal tar pitch, coal tar enamel, epoxy powder coating, and three-layer composite structures, epoxy coal tar pitch cold-applied tape (PF type), and rubber-plastic epoxy coal tar pitch cold-applied tape (RPC type). Currently, the most widely used pipe anti-corrosion methods are three-layer PE composite structures, single-layer powder epoxy, PF-type cold-applied tape, and RPC-type cold-applied tape.

Petroleum asphalt is widely available and inexpensive. However, it results in poor working conditions, difficulty in guaranteeing quality, and serious environmental pollution.

Epoxy coal tar pitch is easy to apply, but the curing time of the coating is long; it is greatly affected by the environment, unsuitable for field operations, and difficult to apply below 10℃.

Epoxy powder coating, applied via electrostatic spraying, provides excellent fusion and strong adhesion to pipes coated with the same material. However, epoxy powder has poor water resistance (high water absorption rate, reaching 0.83%), posing challenges to cathodic protection design. It also requires sophisticated on-site equipment, is difficult to operate, and is challenging to control in terms of quality.

3PE heat-shrinkable material offers strong pipe corrosion protection and sealing, high mechanical strength, excellent water resistance, stable quality, convenient construction, good applicability, and no environmental pollution. PE has low water absorption (below 0.01%) and combines the high strength of epoxy with the low water absorption of PE and the flexibility of hot melt adhesive, resulting in high corrosion resistance and reliability. Its disadvantage is a higher cost compared to other jointing materials.

PF and RPC-type cold-applied tapes are easy to apply. The three types of matching setting adhesives allow PF-type epoxy coal tar cold-applied tape to be applied in any environment, season, and temperature condition.

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