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.

S32750 or Duplex 2507

Duplex 2507 is a super duplex stainless steel developed for applications that demand high strength and corrosion resistance. Alloy 2507 has 25% chromium, 4% molybdenum, and 7% nickel.

This high molybdenum, chromium and nitrogen content causes high resistance to chloride pitting and crevice corrosion attack and the duplex structure provides 2507 with exceptional resistance to chloride stress corrosion cracking.

Using Duplex 2507 must be restricted to applications below 600° F (316° C). Extended elevated temperature exposure can reduce both the toughness and corrosion resistance of alloy 2507.

Duplex 2507 has good mechanical properties. Often a light gauge of 2507 material can be used to achieve the same design strength of a thicker nickel alloy. The resulting weight savings can considerably reduce the overall cost of fabrication.

Properties of Super Duplex Steel 2507 or S32750

  • High resistance to chloride stress corrosion cracking.
  • High Strength.
  • Combination of properties given by austenitic and ferritic structure.
  • Good weldability and workability.
  • Superior resistance to chloride pitting and crevice corrosion.
  • Good general corrosion resistance.
  • Suggested for applications up to 600° F.Stainless Steel S32760

Applications of S32750 Super Duplex Stainless Steel

The applications of S32750 super duplex stainless steel are:

  • Desalination Equipment.
  • Chemical process pressure vessels, piping and heat exchangers.
  • Marine Applications.
  • Flue Gas Scrubbing Equipment.
  • Pulp & Paper Mill Equipment.
  • Offshore Oil production/technology.
  • Oil and gas industry equipment.

Chemical Composition

Chromium24.0 - ­26.0
Nickel6.0 ­- 8.0
Molybdenum3.0 - ­5.0
Carbon0.03 max
Copper0.5 max
Nitrogen0.2 - ­0.3
Manganese1.20 max
Silicon0.80 max
Phosphorus0.035 max
Sulphur0.02 max