Product Information of Super Duplex Stainless Steel Pipes

Super Duplex Stainless Steel Pipes are high-performance piping products designed for the most demanding and highly corrosive industrial environments. They are an advanced version of standard duplex stainless steel.


Key Characteristics

Super duplex stainless steel is a highly alloyed, two-phase (duplex) material with a microstructure containing nearly equal amounts of austenite and ferrite.The term "super" refers to its enhanced performance, which is achieved by significantly increasing the content of key alloying elements: Chromium (Cr), Molybdenum (Mo), and Nitrogen (N).

Property

Super Duplex Pipes

Comparison to Standard Stainless Steel (e.g., 316L)

Corrosion Resistance

Exceptional. Highly resistant to pitting (PREN > 41), crevice corrosion, and chloride stress corrosion cracking.

Significantly Superior.

Mechanical Strength

Very High. Yield strength is about twice that of standard austenitic grades (304/316).

Much Higher. Allows for thinner wall pipe sections.

Chemical Composition

High content of Cr (approx. 24-26%), Ni (approx. 6-8%), Mo (approx. 3-5%), and N.

Higher alloy content overall.

Operating Temperature

Good toughness down to sub-zero temperatures, but restricted to a maximum service temperature of approximately 300°C to avoid embrittlement.


 Common Grades

The most popular super duplex stainless steel grades used for pipes and fittings are:

  • UNS S32750 (Grade 2507 / F53): This is the most common super duplex grade. It contains about 25% Cr, 7% Ni, and 4% Mo.
  • UNS S32760 (Grade F55 / Zeron 100): This grade often includes additions of Copper (Cu) and Tungsten (W) for even greater resistance to certain acids and environments, especially those found in the oil and gas sector.

  •  Primary Applications

    The combination of extreme strength and superior corrosion resistance makes Super Duplex pipes essential for critical infrastructure in aggressive media:

  • Offshore Oil and Gas: Subsea pipelines, risers, manifolds, process piping, and structural components on floating production, storage, and offloading (FPSO) vessels, especially in systems exposed to seawater and sour gas.
  • Desalination Plants: Used for high-pressure piping, heat exchangers, and brine lines, which must withstand highly concentrated salt solutions and chlorides.Chemical Processing: Equipment, pipelines, and pressure vessels for handling harsh, aggressive acids and corrosive chemicals.
  • Pulp and Paper Industry: Used in bleaching systems and liquor tanks that operate in chloride-rich environments.
  • Marine Engineering: Components exposed directly to the corrosive effects of seawater.
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