Common Methods and Connections for 3PE Anti-corrosion Steel Pipes

First, Common Methods for 3PE Anti-corrosion Steel Pipes

1. Steel pipe corrosion protection generally employs two main methods: external coating and cathodic protection.

2. Although most of the steel pipe's surface is covered by the coating, even a small leak can lead to an incredible corrosion rate, perforation, or cracking. Therefore, in steel pipe corrosion protection, the coating system and cathodic protection are generally used in combination to achieve a 99.99% coverage rate to prevent unimaginable consequences later.

3. Cathodic protection for steel pipe corrosion is divided into sacrificial cathodic protection and impressed current cathodic protection.

4. The purpose of using a coating in 3PE anti-corrosion steel pipes is to form a continuous insulating layer, directly insulating the metal from the electrolyte in direct contact, thus preventing proper electrolytic reactions.

5. Discontinuities in the coating application process are called leaks. These leaks mainly occur during coating, transportation, or installation, and may also be caused by coating aging, soil stress, or pipe movement in the soil, without timely detection of third-party damage.

Second, Connection Methods for 3PE Anti-corrosion Steel Pipes

(1) Welding Connection: If disassembly is generally unnecessary, welding can be used. Compared to traditional connection methods, this method is simple in structure, allowing direct connection of components of any type; it is economical in terms of materials, does not weaken the cross-section; it is easy to manufacture and process, and can be automated; it provides good sealing and high structural rigidity. However, it is not suitable for emergency repairs in today's environment.

(2) Flange Connection: Flanges are welded to the pipe ends. For connections between two pipe ends, flanges are first welded or threaded onto each pipe end, and then the two welded flanges are joined together, with a gasket in the center.

(3) Grooved pipe fitting connection: This connection method is the main technology for connecting liquid and gas pipelines. The pipe fittings required for this connection method include: rigid joints, flexible joints, mechanical tees, and grooved flanges such as elbows, tees, crosses, reducers, blind flanges, etc.