A submarine pipeline (also known as subsea pipeline or offshore pipeline) is a pipeline that is laid on the seabed or below it inside a trench. In some cases, the pipeline is mostly on-land but in places it crosses water expanses, such as small seas, straights and rivers. Submarine pipelines are used primarily to carry oil or gas.It is used to bring the resource to shore Sizeable pipeline construction projects need to take into account a large number of factors, such as the offshore ecology, geohazards and environmental loading

Water and oil&gas will cause corrosion to pipeline for submarine in subsea pipeline construction,not only bring economic loss ,also can cause environmental pollution.So the pipe corrosion is necessary.one possibility is to jacket the subsea piping with a material that resists corrosion.During this finishing procedure, the pipeline are coated with 3LPE to maintain continuity with the rest of the pipe.Another way is to develop and use new type of corrosion resistant alloy steel pipe.

 API 5L and DNV OS F101 standard are used in the design of submarine pipelines.

In API 5L standards, submarine pipeline mainly use carbon seamless steel pipe(SML), high-frequency resistance welding pipe(HRW), straight seam submerged arc welding pipe(SAW,UOE are commonly use).SML pipe is generally used in small diameter, poor transport temperament occasion. HRW pipe manufacturing process is simple, high yield, and lower cost compared with other steel pipe.UOE pipe is widely used in the submarine pipeline engineering with stable quality, high reliability, high bearing capacity, and good low-temperature toughness. 

Submarine pipeline are generally designed in strength grades up to x65,the current trend is towards linepipe in grade x65,x70and x80with a wall thickness 5mm up to 40mm.