The corrosion protection method for anti-corrosion spiral steel pipes is generally to use coating anti-corrosion, and increasingly, composite materials or composite structures are being adopted. These materials and structures must possess good dielectric properties, physical properties, stable chemical properties, and a wide temperature adaptability range.

1. External anti-corrosion coating: Types of coating materials and application conditions for the external wall of spiral steel pipes.

Inner wall anti-corrosion coating: A thin film applied to the inner wall of the pipe to prevent internal corrosion, reduce frictional resistance, and increase flow rate. Commonly used coatings include amine-cured epoxy resin and polyamide epoxy resin, with a coating thickness of 0.038–0.2 mm. To ensure a strong bond between the coating and the pipe wall, the inner wall of the pipe must be surface-treated. Since the 1970s, there has been a trend to use the same material for the coating of the inner and outer walls of pipes, so that the coating of the inner and outer walls can be carried out at the same time.

2. Anti-corrosion and heat-insulating coating: On medium and small diameter pipelines for transporting hot crude oil or fuel oil, in order to reduce heat loss from the pipeline to the soil, a composite layer of heat insulation and anti-corrosion is added to the outside of the pipeline. The commonly used insulation material is rigid polyurethane foam, which is suitable for temperatures ranging from -185 to 95°C. This material is soft in texture. To improve its strength, a layer of high-density polyethylene is applied to the outside of the insulation layer to form a composite material structure, which prevents groundwater from seeping into the insulation layer.

Time：21/10/2026 16:02:26

The coating scheme for anti-corrosive spiral steel pipes is determined by the operating environment.

The three-layer polyethylene (3PE) coating system combines epoxy powder, an adhesive layer, and a polyethylene layer to form a structurally stable protective barrier.

Epoxy coal tar coating involves the alternating application of epoxy coal tar paint and glass fiber cloth, creating a water- and corrosion-resistant coating system. Internal cement mortar lining forms a smooth inner surface on the pipe wall, helping to reduce flow resistance.

Epoxy powder coating utilizes high-density polyethylene as a base material, balancing mechanical strength with corrosion resistance. Each process has its own specific advantages; the appropriate method should be selected based on the conveyed medium and installation conditions.

Time：14/10/2026 16:38:00

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