What Are The Commonly Used Welding Methods For Long-distance Pipeline Welding

At present, the commonly used installation and welding methods for long distance pipelines at home and abroad mainly include electrode arc welding, manual tungsten argon arc welding, and melting and gas shielded semi-automatic welding, including active gas shielded STT semi-automatic welding, semi-automatic melting and argon arc welding, and semi-automatic active gas shielded welding. , Self-shielded flux-cored wire arc welding, submerged arc welding, melting ji active gas shielded automatic welding and flash butt welding, etc. Except for flash butt welding, other welding methods have been applied in China’s West-East Gas Pipeline Project, and the main welding methods are self-shielded flux-cored wire automatic welding and molten active gas shielded automatic welding.

The following categories are:

1. Electrode arc welding (SMAW)

(1) Advantages of electrode arc welding

The process is flexible and adaptable. The heat-affected zone is small and the quality is good. It is easy to control deformation and improve stress through process adjustment. The equipment is simple and easy to operate.

(2) Insufficient

High requirements for welders. The welder’s operating skills and on-site performance, and even the welder’s mental state directly affect the welding process, thus affecting the quality of the weld. The working conditions are poor. Low productivity.

2. Submerged arc welding (SAW)

(1) Advantages of submerged arc welding

high productivity. The welding specification is stable, the molten pool protection effect is good, and the welding seam quality is good. Good working conditions.

(2) Disadvantages of submerged arc welding

It is difficult to weld in a spatial position, and is only suitable for welding in a nearly horizontal position. It is difficult to weld easily oxidized metal materials. Not suitable for welding thin plates and short welds. High requirements for the assembly quality of weldments. The equipment is complex.

3. FCAW/GMAW welding

(1) Advantages of FCAW/GMAW

High productivity. It has a wide range of applications and is easy to realize automation and all-position welding in the welding process. For CO2 welding, its anti-rust ability is strong; for rich argon welding, its arc is stable, the range of weldable materials is wide, and the welding quality is high.

(2) Insufficient

It has poor wind resistance and is not suitable for welding in windy places or in the open air. For CO2 welding, metals that are difficult to weld and easily oxidize and the shape is not beautiful. The arc light radiation is strong, because the open arc is used in welding and the current density used is large.