Welded steel pipe is a type of material used in the construction and manufacturing industry. These pipes are produced by welding steel plates together to create pipes of varying lengths and diameters.

The main uses of welded steel pipes include:

1. Water and gas transportation: Welded steel pipes are commonly used to transport water, oil, natural gas, and other liquids from one point to another in water supply, oil distribution, and gas supply systems.

2. Construction and electromechanical: In construction projects and the electromechanical industry (Heating, Ventilation, and Air Conditioning), welded steel pipes are often used to create load-bearing structures, water supply systems, air supply systems, and oil transportation systems.

3. Mechanical and manufacturing: Welded steel pipes are also used to produce mechanical equipment such as tanks, containers, lines, and various components in the manufacturing industry.

4. Building structures: In structural construction applications, welded steel pipes are often used as part of load-bearing structures, including bridges, warehouses, buildings, and other public infrastructure.

Welded steel pipes come in many types with different physical and chemical properties, depending on the specific application. They are typically manufactured in various sizes, diameters, and thicknesses to serve diverse applications in other industries."