Transportation temperature of LNG must be maintained at - 163 C, which requires the use of steel pipes with stable physical and mechanical properties at low temperatures.


Seamless steel pipes for offshore platform legs are affected by alternating loads from waves. Therefore, high-grade (X100/X100Q) large-diameter large-wall steel tubes with large deformation resistance and fatigue resistance are needed.


Submarine oil and gas pipelines withstand high pressures in deep water (for example, 3000 meters deep). Plastic deformation is easy to occur in the course of laying, and steel pipe is easy to corrode. This requires pipeline steel to resist collapse, fatigue and corrosion.


In short, offshore oil and gas pipelines are developing towards low carbon helium microalloying and bimetallic composite pipes. High frequency straight seam welded pipe and underwater straight-straight welded pipe are mainly used in submarine oil and gas pipelines.