The most widely used anti-corrosion layers for steel pipelines include petroleum asphalt, PE jacket, and PE foam jacket, epoxy coal tar pitch, coal tar enamel paint, epoxy powder and three-layer composite structure, epoxy coal tar pitch cold wrap (PF type), Rubber-plastic epoxy coal tar pitch cold-wrapped tape (RPC type), etc., the most widely used pipeline anti-corrosion methods are three-layer PE composite structure, single-layer powder epoxy, PF-type cold-wrapped tape, RPC-type cold-wrapped bring.
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.
Epoxy powder anti-corrosion, an electrostatic spraying method, good fusion with the same material anti-corrosion pipe body, strong adhesion, but epoxy powder has a poor waterproof (high water absorption, up to 0.83%), designed for cathodic protection bring certain difficulties. On-site equipment has high requirements, is difficult to operate, and the quality is not easy to control.
3PE heat-shrinkable material has strong anti-corrosion sealing, high mechanical strength, strong waterproof, stable quality, convenient construction, good applicability, and does not pollute 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 has high anti-corrosion reliability. The disadvantage is: that compared with the cost of other filling materials, high cost.
The construction of PF type and RPC type cold-wound tape is simple and easy, and the matching three kinds of setting glues make the PF type epoxy coal tar pitch cold-wound tape can be constructed in any environment, any season, and any temperature conditions.
The characteristics of 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.