Duplex Stainless Steels, also referred to as austenitic­ferritic stainless steels, are a family of grades having around equal proportions of austenite and ferrite.

These steels have a duplex microstructure which contributes to their high strength and high resistance to stress corrosion cracking.

Duplex steels offer high resistance to uniform and local corrosion because of their high content of nitrogen, chromium and molybdenum. Duplex stainless steels have good weldability.

There are three groups of duplex stainless steels that include the following:

  • Lean Duplex
  • Standard Duplex
  • Super Duplex.

S32760 Super Duplex Stainless Steel

S32760 super duplex stainless steel is developed to be used in aggressive environments. Properties of S32760 include toughness, high strength, corrosion resistance in a large number of organic and inorganic acids.

Finally it features high resistance to strong alkalis and resists corrosion in a number of non­oxidizing acids. While involving extended exposure to temperatures more than 572F use of S32760 is not recommended.

The chemical composition of S32750 and S32760 are similar; however, the latter contains slightly more copper and tungsten. The copper content (min. 0.5, max 1.0) permits excellent resistance to corrosion in many non­oxidizing and mineral acids like hydrochloric and sulfuric acid.

Properties of Super Duplex Steel S32760

The properties of super duplex steel S32760 are:

  • Guaranteed corrosion performance (PREn ≥ 40).
  • Excellent corrosion resistance in mineral acids such as hydrochloric and sulfuric acids.
  • High resistance to pitting and crevice corrosion.
  • Excellent resistance to stress corrosion cracking in both chloride and sour environments.
  • High resistance to erosion, corrosion and corrosion fatigue.
  • Excellent mechanical properties.
  • Possibility for weight reduction over austenitic, standard duplex and nickel base alloys.
  • Good weldability.

Applications of Super Duplex Stainless Steel S32760

The applications of S32760 super duplex stainless steel are:

  • Oil and gas industry applications.
  • Pollution control.
  • Pulp and paper.
  • Desalination.
  • Mining and mineral industries.
  • Marine industries.
  • Power generation.
  • Flue­gas desulfurization.
  • Chemical, pharmaceutical.

Chemical Composition

Chromium24.0 - ­26.0
Nickel6.0 ­- 8.0
Molybdenum3.0 - ­4.0
Carbon0.030 max
Tungsten0.5 - ­1.0
Copper0.5 - ­1.0
Nitrogen0.2 - ­0.3
Manganese1.00 max
Silicon1.00 max
Phosphorus0.03 max
Sulphur0.01 max