Carbon steel valve

Seamless tubes have a hollow cross-section but no seams around the periphery. They are made from tube billets as raw materials, processed into rough tubes through hot piercing and other procedures, and then formed by cold rolling or cold drawing. Their inspection and shaping must be handled offline.

Welded pipes (referred to as "welded pipes" for short) have a hollow cross-section but with welding seams around the periphery. They are made from plates (flat plates or rolled plates) as raw materials, which are rolled into shape by machines and molds, and then the seams are welded together.

Pipe fittings are the general term for components in pipeline systems that play roles such as connection, control, direction change, diversion, sealing, and support. According to different processing techniques, they are classified into four major categories: butt-welded pipe fittings (including those with and without welds), socket-welded and threaded pipe fittings, and flanged pipe fittings.