What is API 5L

API 5L generally refers to the implementation standard of pipeline pipes, which include seamless steel pipes and welded steel pipes.The national standard GB/T 9711-2011 steel pipes for oil and gas industry pipeline transmission system is prepared according to API 5L.

At present, the welded steel pipes commonly used in oil pipelines include spiral submerged arc welded pipe (SSAW), longitudinally submerged arc welding pipe (LSAW), and electric resistance welded pipe (ERW). Seamless steel pipes are generally selected when the diameter of the pipe is less than 152mm.

GB/T 9711-2011 specifies the manufacturing requirements for seamless steel pipes and welded steel pipes of two product specification levels (PSL1 and PSL2) used in oil and gas industry pipeline transmission systems. Therefore, this standard is only applicable to seamless steel pipes and welded steel pipes for oil and gas transmission, not to cast iron pipes.

The steel grades of raw materials for API 5L steel pipes include GR.B, X42, X46, X52, X56, X60, X70, X80, etc. The requirements for raw materials and production are also different, but the carbon equivalent between different steel grades is strictly controlled.