First of all, coating protection is a common means of corrosion protection for steel pipe direct-buried pipe. Among them, 3PE coating (three-layer polyethylene coating) is widely used due to its excellent anti-corrosion performance. The coating consists of a bottom layer of fused epoxy powder, an intermediate layer of adhesive and an outer layer of polyethylene. It has good adhesion, corrosion resistance and mechanical properties, and can effectively block the corrosion of corrosive media on steel pipes.
Secondly, polyurethane coating is also one of the commonly used anti-corrosion measures. Polyurethane coating has excellent wear resistance, water resistance and chemical corrosion resistance, and the coating has good elasticity and can adapt to the expansion and contraction deformation of the pipeline. It has a fast curing speed and can be quickly constructed at room temperature to form a continuous and dense protective film, providing good anti-corrosion protection for steel pipes.
Furthermore, cathodic protection technology is also an important measure for the anti-corrosion of steel pipe direct-buried pipe. The sacrificial anode method is a commonly used cathodic protection method. By connecting the sacrificial anode to the steel pipe, the sacrificial anode corrodes first in the soil electrolyte environment, providing the steel pipe with a cathodic protection current, thereby inhibiting the occurrence of corrosion reactions.
In addition, impressed current cathodic protection is also an effective anti-corrosion measure. This method uses a constant potential instrument and other equipment to connect the negative electrode of the DC power supply to the steel pipe, and the positive electrode to the auxiliary anode, and applies a cathodic protection current to the surface of the steel pipe, so that the surface of the steel pipe is in a cathodic polarization state, thereby preventing corrosion.
In addition to the above measures, FRP coating and plastic isolation layer are also feasible solutions for the anti-corrosion of steel pipe direct-buried pipe. FRP coating can effectively isolate the contact between the steel pipe and the soil, and prevent the corrosive substances in the soil from corroding the steel pipe. The plastic isolation layer, such as polyethylene film, can effectively block the contact between moisture and corrosive substances in the soil and the steel pipe, and play a role in anti-corrosion and corrosion mitigation.
Finally, regular anti-corrosion inspection and maintenance are also an important part of ensuring the long-term and stable operation of steel pipe direct-buried pipe. Through equipment such as spark leak detectors and coating thickness gauges, the anti-corrosion coating of the steel pipe is regularly inspected to promptly discover and deal with potential corrosion problems.
