Welding procedure：round tube billet → heating → perforation → three-roller cross-rolling,  continuous rolling or extrusion → tube removal → sizing (or reduced diameter) → cooling → straightening → hydraulic test (or flaw detection) → marking. 

Working pressure refers to the pressure of pipes, fittings, valves, etc. under normal operating conditions.

Take the seamless steel pipe as an example, pipe wall thickness tolerance affect the quality. Pay attention to this, you will get a better pipe.

The pressure rating of the pipeline includes two parts: The nominal pressure level of standard fittings expressed in nominal pressure; The wall thickness grade of standard pipe fittings expressed in wall thickness grade.

The raw materials commonly used in pipelines are: plates, pipes and forgings.There is the introduction of these three pipe weight calculation methods.

Sch 40 black steel pipe is uncoated steel, also known as black steel.