The welding of titanium pipes can be carried out using various welding methods, including but not limited to:

1. Tungsten inert gas arc welding (GTAW): suitable for butt, corner, and lap welding of titanium and titanium alloy plates, pipes, and special-shaped parts with a thickness of 0.5-10mm. This method has high weld quality and small deformation, but requires argon gas protection to avoid weld oxidation or nitrification contamination.

2. Electron beam welding (EBW): suitable for butt, corner, and lap welding of titanium and titanium alloy plates, pipes, and special-shaped parts with a thickness of 0.1-150mm. It can be carried out in vacuum to avoid gas pollution, has a large weld depth to width ratio and large deformation, and is efficient.

3. Laser welding (LW): suitable for butt, corner, and lap welding of titanium and titanium alloy sheets, pipes, and special-shaped parts with a thickness of 0.1-10mm. It can be carried out in the atmosphere, only requiring argon gas protection before and after blowing. It has a large weld depth to width ratio and small deformation, fast speed, and can achieve automated or robotic operations.

4. Plasma arc welding (PAW): suitable for butt, corner, and lap welding of titanium and titanium alloy plates, pipes, and special-shaped parts with a thickness of 0.5-15mm. It operates in the atmosphere, only requiring argon gas protection before and after blowing, with a large weld depth to width ratio and small deformation, and high efficiency.

5. Brazing (BW): Suitable for butt, corner, and lap welding of titanium and titanium alloy plates, pipes, and special-shaped parts with a thickness of 0.1-3mm.

6. Melting electrode argon arc welding (MIG welding): suitable for welding medium thickness titanium materials, using direct current reverse connection method.

7. Resistance welding: Due to the high electrical resistivity and low thermal conductivity of titanium, resistance welding is more suitable.