Super Duplex • UNS S32750 • WNR 1.441

Super Duplex stainless like S32750, is a mixed microstructure of austenite and ferrite (50/50) which has improved strength over ferritic and austenitic steel grades. The main difference is that Super Duplex has a higher molybdenum and chromium content which gives the material greater corrosion resistance than standard duplex grades.

The balanced duel phase microstructure combines high strength with cost effective corrosion resistance particularly in high chloride environments. Super Duplex has the same benefits as its counterpart – it has lower alloying costs when compared with similar ferritic and austenitic grades with equipment corrosion resistance in chloride containing environments due to the material’s increased tensile and yield strength. In many cases this gives the purchaser the welcomed option of purchasing smaller thicknesses without the need to compromise on quality and performance.

Available tube product forms

Typical Applications

Typical manufacturing specifications

  • ASTM A789
  • ASME SA-789
  • ASME SA-790
  • Also individual customer specifications.

Industries predominantly using this grade            

Technical Data

Mechanical Properties

Temper Annealed
Tensile Rm 115 ksi (min)
Tensile Rm 800 MPa (min)
R.p. 0.2% Yield 80 ksi (min)
R.p. 0.2% Yield 550 MPa (min)
Elongation (2” or 4D gl) 15 % (min)

Physical Properties (Room Temperature)

Specific Heat (0-100°C) 500°K-1
Thermal Conductivity 15 W.m -1.°K-1
Thermal Expansion 11 mm/m/°C
Modulus Elasticity 200 GPa
Electrical Resistivity 8.12 μohm/cm
Density 7.8 g/cm3

Chemical Composition (% by weight)

Element Min Max
C - 0.03
Cr 24 26
Cu 0.5 1
Mn - 2
Mo 3 5
N 0.24 0.35
Ni 6 8
P - 0.35
S - 0.015
Si - 1
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