Duplex stainless steels, called duplex because of their mixed microstructure of about equal ferrite and austenite proportions, are a family of grades that differ in corrosion performance depending on their alloy material.
Super Duplex contains 7% nickel, 25% chromium, 3.6% molybdenum, copper, tungsten and nitrogen, and is heavily alloyed steel with high PREN for use in harsh environments.
The alloy in the annealed state consists of about 40-50 percent ferrite. In spite of maintaining the corrosion resistance of the austenitic grades, the super duplex microstructure has the high strength of the ferritic grades. As a functional solution to chloride-induced stress cracking, it is normal to see Super Duplex Steel being used. It also has excellent resistance in sour-gas conditions to sulphide-stress corrosion cracking.
Super Duplex UNS S32750 Flanges allow the material to avoid pitting and corrosion of the crevice. These flanges are also resistant to the cracking of chloride stress corrosion, erosion-corrosion, fatigue of corrosion, and general acid corrosion. They are well welded and have very high mechanical strength.
UNS S32760 Super Duplex flanges are well known for their high impact strength and are used in industries such as oil and gas applications, seawater, subsea pipework systems, heat exchangers and more.
The properties of Super Duplex flanges are commonly used in the development and exploration of offshore gas oil, heat exchangers, chemical and petrochemical manufacturing. A Pitting Resistance Equivalent that guarantees high resistance to pitting corrosion is usually given with Super Duplex Steel Flanges. Super duplex stainless steel flanges are primarily accessible as an inexpensive alternative to stainless steels of the 300 series.
Benefits of Super Duplex Flanges
- High power
- High pitting resistance, resistance to crevice corrosion.
- Strong resistance to cracking by stress corrosion, corrosion fatigue and erosion,
- Excellent resistance to the cracking of chloride stress-corrosion
- Elevated thermal conductivity
- Low thermal expansion coefficient
- Strong corrosion resistance to sulphide stress,
- Low thermal expansion and greater conductivity of heat than austenitic steels,
- Strong performance and weldability.
Applications of Super Duplex Flanges
- Heat exchangers, tubes and pipes for gas and oil processing and handling,
- Heat exchangers and pipes in plants for desalination,
- Components, mechanical and structural,
- FGD systems from the power sector,
- Pipes in process industries that treat chloride containing solutions,
- Utility and industrial systems, rotors, fans, shafts and press rolls that can use high corrosion fatigue strength,
- Cargo containers, boats, gas tanker piping and welding consumables.
- High-strength and resistant wiring.
- Chemical processing, transport and storage, Pipes for production and transportation Oil and gas exploration and offshore rigs.
- Oil and gas refining, Marine environments, Pollution control equipment, Pulp & paper manufacturing, Chemical process plant, Structural and mechanical components, Heat exchangers, Cooling pipes