What are duplex stainless steel applications?

Duplex stainless steel is a stainless steel in which the ferrite and austenite phases in the solid solution structure each account for about 50%. It not only has good toughness, high strength and excellent resistance to chloride corrosion, but also resistance to pitting corrosion and intergranular corrosion, especially stress corrosion resistance in chloride environment. Many people do not know that the duplex stainless steel applications is not less than that of austenitic steels.

Application of duplex stainless steel in marine engineering – Coastal construction and bridges

Coastal buildings face natural conditions of high humidity and high salt. For the new Doha International Airport in Qatar, the Persian Gulf country, it will also be affected by strong ultraviolet rays, high temperatures, and abrasion.

Traditional building materials have insufficient resistance to pitting corrosion. The construction party initially suggested using titanium alloys to build airport roofs. However, due to the difficulty and high cost of construction, they had to abandon the use of this material, and instead consider using durable, more life-cycle cost. Advantageous duplex stainless steel.

In the end, people chose ATI 2003 economical duplex stainless steel. More than 1,500 tons of duplex stainless steel sheets were treated with a matt surface to build the world’s largest wave-shaped stainless steel roof.

Stonecutters Bridge in Hong Kong, China has a design life of 120 years and is maintenance-free. This cross-bay expressway bridge connecting Hong Kong and Shenzhen used about 2,000 tons of duplex 2205 steel plates to make the outer surface structure of the upper part of the pylon, and about 1,250 tons of 2205 and 316 were used as highway steel bars. The Hong Kong-Zhuhai-Macao Bridge, the longest cross-sea bridge in the world, which was completed in October last year, used 8,200 tons of duplex stainless steel steel bars, which are mainly used in the bridge’s platform, tower and pier.

• 

• 

Thanks to the good toughness of duplex stainless steel, economical UNS 32304 has been used to build wind- and fire-resistant buildings on offshore platforms.

---

Oil and gas extraction

In oil and gas production, duplex stainless steel is mainly used in downhole production pipelines, injection devices for oil field gas wells, offshore centrifugal separators, subsea oil and gas pipeline systems, heat exchangers, and surface operating systems, etc. It is especially suitable for applications containing Cl, CO2 , H2S in acidic environment without corrosion inhibitor.

2500 tons of UR45N duplex stainless steel was used in the Norwegian Statoil project to reduce equipment weight; UR52N super duplex stainless steel was used in the North Sea oil field project in the United Kingdom to manufacture oil and gas manifolds and pipelines; oil and gas wells in Alaska, the Gulf of Mexico and other places in the United States SAF2507 super duplex stainless steel is used in production, offshore oil production platform facilities and oil and gas pipelines.

In addition, thanks to the addition of copper to further improve the strength and corrosion resistance, Ferralium225-SD50 duplex stainless steel has been used to manufacture 7000m deep subsea equipment and cable containers, as well as subsea locators and controllable deep-sea acoustics. Release the pressure housing and load-bearing parts of the transponder.

---

Desalination

Due to the high concentration of seawater chloride ions, the equipment and pipelines of the seawater desalination system will face severe corrosion. Traditional austenitic stainless steel often suffers from local corrosion damage such as pitting corrosion, crevice corrosion, and stress corrosion.

Duplex stainless steel happens to perform well in the above-mentioned corrosion types and becomes one of the main materials. Among them, the evaporator condenser tube in the multi-stage flash seawater desalination method mostly uses 2507 super duplex stainless steel tube instead of titanium or copper-nickel alloy. The flash chamber shell can use 2205 duplex stainless steel pipes by stainless steel pipe fittings manufacturers. The latter has been adopted by the Libyan desalination plant. The high-pressure pipeline of the reverse osmosis method and the high-pressure pump of the high-chloride environment use 2507 steel, which is comparable to the 6Mo-containing super austenitic stainless steel, and has been used in the new Ashkelon plant in Israel.

China’s Caofeidian desalination project uses 300 tons of 2205 steel plates to manufacture multi-stage flash evaporation equipment.