QUANGE GUANYE
Blog
15
2025
-
07
Demand for steel pipes used in ocean engineering is growing, with corrosion resistance
With the rapid development of offshore oil and gas exploitation and offshore wind power, the demand for special steel pipes
With the rapid development of offshore oil and gas development and offshore wind power, the demand for special steel pipes that are resistant to seawater corrosion and wind and wave impact has significantly increased. Due to the harsh application environment, these steel pipes have special requirements in terms of material selection and corrosion protection, and their performance level is an important reflection of the company's core competitiveness.
The characteristics of steel pipes for marine engineering focus on corrosion resistance and structural strength. Seawater pipelines use super austenitic stainless steel (such as 254SMO), with chromium, molybdenum, and nitrogen content exceeding 30%, and pitting resistance equivalent (PREN) ≥40 in seawater with a salinity of 3.5%, with corrosion resistance more than twice that of ordinary 316 stainless steel. Steel pipes for offshore platform legs use quenched and tempered high-strength steel (such as E690), with a yield strength ≥690MPa, capable of withstanding alternating loads generated by wave impact, and a fatigue life of over 1 million cycles.
Its advantages are particularly prominent in marine environments. Compared with traditional coated carbon steel, stainless steel pipes have more durable corrosion resistance, reducing the need for underwater painting, cathodic protection, and other maintenance measures, lowering the life-cycle cost. In deep-sea areas (water depth exceeding 1000 meters), the pressure resistance of steel pipes is crucial. Thick-walled seamless steel pipes (wall thickness up to 50mm) are used, capable of withstanding external pressure exceeding 10MPa, ensuring that the pipes do not become unstable and fail in the deep-sea environment. In addition, the weldability of the steel pipes allows for on-site connection on offshore platforms, adapting to the complex installation requirements of the project.
Applications cover multiple marine engineering fields. In offshore wind power projects, large-diameter steel pipes for monopile foundations have diameters of 6-8 meters and lengths exceeding 60 meters, spirally embedded in the seabed to provide stable support for wind turbines. Subsea oil and gas pipelines use double-layer insulated steel pipes, with the inner layer transporting oil and gas, and the outer protective pipe using corrosion-resistant alloys, with insulation material filled in between, suitable for deep-sea low-temperature environments. The water intake network of seawater desalination plants uses seawater corrosion-resistant steel pipes to ensure that no rust contamination occurs during raw water transportation, improving the quality of desalinated water.
To meet the high standards of marine engineering, steel pipe companies strengthen cooperation with research institutions to conduct research on deep-sea steel composition optimization and welding processes. Currently, many domestic companies have the ability to produce high-end steel pipes for marine engineering, and product performance has reached internationally advanced levels, gradually replacing imported products.
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