The application of steel pipes in marine engineering is very common.
There are roughly three types of steel pipes in the two major systems of shipbuilding and marine engineering: steel pipes in conventional systems, steel pipes used in construction, and steel pipes for special purposes. Different ships and marine projects have both conventional and special systems.
The service life of ships is generally about 20 years, and the service life of steel pipes in marine engineering can reach at least 40 years. In addition to conventional systems, there are also special drilling and production equipment systems, as well as processing flow systems for crude oil, liquefied petroleum gas and liquefied natural gas in offshore engineering.
Through calculation, it is found that the annual consumption of large-diameter straight seam steel pipes (LSAW)
for marine use is 5 million tons, about 500,000 pipes, of which 70% of the steel pipes are connected. Only a 300,000-ton super-large oil tanker can use dozens of kilometers of steel pipes and pipe fittings, and the steel pipe content alone is around 1,000-1,500 tons. Of course, the amount of steel pipes used in the hull structure of 40,000 tons is still relatively limited. Also, considering the same kind of ships, there are a lot of other ships to build. For a 300,000-ton super-large FPSO, the number of pipes exceeds 40,000 and the length exceeds 100 kilometers, which is 3-4 times that of the same tonnage. Therefore, the shipbuilding industry has become a major user of the steel pipe industry.
Special-purpose steel pipe: refers to the special steel pipe used in a specific working environment and working medium. The submarine oil pipeline is a typical special steel pipe, which is in great demand and has the characteristics of high strength, small tolerance and good corrosion resistance.
In addition to the conventional and special systems mentioned above, thick-walled straight seam steel pipes are used in many structures, such as jackets, underwater steel piles, casings, mooring brackets, helicopter channels, flare towers, etc. This kind of thick-walled straight seam steel pipe has many specifications, high raw material, and has the same diameter, different diameter, different wall thickness, Y-type, K-type, T-type pipe joints. Such as jackets, steel piles, wellhead water jackets, etc., mostly large-diameter thick-walled straight seam steel pipes, generally rolled from steel plates.
In addition to the dimensional requirements of thick-walled straight seam steel pipes, its corrosion resistance requirements are also very high. Because the steel pipe is exposed to water and various media in water for a long time, the corrosion of the steel pipe is very serious, so the thick-walled straight seam steel pipe should be treated with anti-corrosion