The anti-corrosion method of anti-corrosion steel pipes generally uses coating anti-corrosion. Let’s learn about the knowledge about coating anti-corrosion.

Coating anti-corrosion is to apply paint evenly and densely on the surface of derusted metal pipes to isolate it from various corrosive media. It is one of the most basic methods of anti-corrosion of steel pipes. Steel pipe anti-corrosion coatings are increasingly using composite materials or composite structures. These materials and structures must have good dielectric properties, physical properties, stable chemical properties and a wide temperature range.

1. Outer wall anti-corrosion coating: types of pipe outer wall coating materials and usage conditions.

②Inner wall anti-corrosion coating: A thin film coated on the inner wall of the pipe in order to prevent corrosion inside the pipe, reduce friction resistance, and increase output. Commonly used coatings include amine-cured epoxy resin and polyamide epoxy resin, with a coating thickness of 0.038 to 0.2 mm. In order to ensure that the coating is firmly bonded to the pipe wall, the inner wall of the pipe must be surface treated. Since the 1970s, there has been a tendency to use the same material for the inner and outer wall coatings of pipes, so that the coating of the inner and outer walls of the pipe can be carried out at the same time.

③Anti-corrosion and thermal insulation coating: On medium- and small-diameter thermal pipelines transporting crude oil or fuel oil, in order to reduce the heat dissipation of the pipeline to the soil, a composite layer of insulation and anti-corrosion is added to the outside of the pipeline. The commonly used insulation material is rigid polyurethane foam, with an applicable temperature of -185~95℃. This material has a soft texture. In order to increase its strength, a high-density polyethylene layer is applied outside the insulation layer to form a composite material structure to prevent groundwater from penetrating into the insulation layer.

2. If the outer protective pipe is a polyethylene pipe, no anti-corrosion is required

Polyethylene is odorless, non-toxic, feels like wax, and has excellent low-temperature resistance (minimum usage Temperature can reach -70~-100℃), has good chemical stability, can resist the erosion of most acids and alkalis (not resistant to acids with oxidizing properties), is insoluble in general solvents at room temperature, has low water absorption, but because it is a linear molecule It can be slowly soluble in certain organic solvents without swelling and has excellent electrical insulation properties.