Materials used to prevent corrosion of steel pipelines include petroleum asphalt, epoxy coal asphalt, adhesive tape, epoxy powder, PE coating, PP coating, etc.
In addition to anti-corrosion materials, there are other methods to prevent corrosion of steel pipelines, such as cathodic protection. By applying an external DC power supply, the steel pipe generates a negative potential to the soil, thereby anti-corrosion the steel pipe; changing the internal structure of the metal, such as using stainless steel Materials or alloy materials with strong corrosion resistance can be used to improve the corrosion resistance of steel pipes.
Commonly used repair methods include petroleum asphalt repair, epoxy coal asphalt repair, anti-corrosion cold-wrapped tape, epoxy powder repair, PE heat shrink material repair, etc.
If the main body of the pipeline is a three-layer PE composite structure, the repair material must be a three-layer PE heat shrink repair material.
A single layer of epoxy powder coating can be repaired in three ways: epoxy powder, primer + anti-corrosion cold-wrapped tape, and PE heat shrink repair.
In addition: the widely used anti-corrosion layers of steel pipelines in China include petroleum asphalt, PE sheath and PE foam sheath, epoxy coal asphalt, coal tar enamel, epoxy powder three-layer composite structure, etc. Two of them are the most widely used currently. The best anti-corrosion method for steel pipelines is a three-layer PE composite structure and a single layer of powder epoxy.
Petroleum asphalt raw materials are widely available and cheap. However, working conditions are poor, quality is difficult to guarantee, and environmental pollution is serious.
Epoxy coal tar pitch is easy to operate, but the covering layer takes a long time to cure and is greatly affected by the environment. It is not suitable for field work and is difficult to construct under temperatures below 0°C.
Anti-corrosion cold-wound tape is easy to operate, adaptable to on-site construction, has high waterproof performance, good strength, and is not greatly affected by the environment.
Epoxy powder anti-corrosion uses electrostatic spraying. It fuses well with anti-corrosion pipe bodies of the same material and has strong adhesion. However, epoxy powder has poor water resistance (high water absorption rate, reaching 0.83%), and is not suitable for cathodic protection design. bring certain difficulties. On-site equipment requirements are high, operation is difficult, and quality is difficult to control.
3PE heat shrinkable materials have strong anti-corrosion and sealing properties for steel pipelines, high mechanical strength, strong waterproofness, stable quality, convenient construction, good applicability, and do not pollute the environment. PE has the characteristics of low water absorption (less than 0.01%), high epoxy strength, low PE water absorption, good hot melt adhesive softness, etc., and has high anti-corrosion reliability. The disadvantage is that the cost is higher compared to the cost of other repair materials.
The characteristics of anti-corrosion cold-wrapped tape and 3PE heat shrink tape are: they are suitable for main anti-corrosion layer pipes of various materials, while other methods are suitable for main anti-corrosion layer pipes of the same or similar materials.
