Introduction of welded pipe 

Welded pipe refers to a type of pipe made from metal strips or sheets that are welded together to form a tubular structure. The welding process can vary depending on the material being used and the specific requirements of the pipe.

There are several methods for welding pipes, including:

Electric Resistance Welding (ERW): This method uses a combination of heat and pressure to create a weld. An electric current is passed through the metal, heating it to the point where it becomes molten and fusing the edges together.

Submerged Arc Welding (SAW): In this method, an arc is formed between a continuously fed electrode and the workpiece. The arc is submerged under a layer of granular flux, which protects the weld zone from contamination and helps in achieving high-quality welds.

Gas Metal Arc Welding (GMAW): Also known as MIG (Metal Inert Gas) welding, this process uses a consumable electrode wire and a shielding gas to protect the weld from atmospheric contamination.

Gas Tungsten Arc Welding (GTAW): Commonly known as TIG (Tungsten Inert Gas) welding, this process uses a non-consumable tungsten electrode and a shielding gas. It's often used for high-quality welds in applications requiring precise control.

High-Frequency Resistance Welding (HFW): This process uses high-frequency electric resistance heating to join the edges of the pipe. It's commonly used for welding API (American Petroleum Institute) grade pipes.