F51 DUPLEX Acciaio inox W. Nr. 1.4462 – UNS S31803 ASTM A182

F51 DUPLEX

F51 DUPLEX UNS S31803 wr. 1.4462  stainless steel is an alloy with a microstructure balanced by 50% austenite and ferrite , offering high mechanical strength and good corrosion resistance. Thanks to its composition, it guarantees good resistance to chloride- induced stress corrosion cracking and can be used in aggressive environments where austenitic stainless steels would not be adequate.

This alloy is used in critical industrial applications, such as oil and gas, chemical, marine, and power generation. F51 DUPLEX S31803 can be supplied with a PREN (Pitting Resistance Equivalent) >34, which ensures high resistance to pitting corrosion.

Reference standards:

  • ASTM A182 F51 (flanges and forgings)
  • ASTM A276, A479 (bars)
  • ASTM A240 (sheet and strip)
  • EN 10088-3 1.4462 (X2CrNiMoN22-5-3)
  • NORSOK MDS D41-D45, D47, D48
  • NACE MR01-75 / ISO 15156 (applications in acidic environments)

Chemical composition (%)

Element Min (%) Max (%)
Chromium (Cr) 21.0 23.0
Nickel (Ni) 4.5 6.5
Molybdenum (Mo) 2.5 3.5
Nitrogen (N) 0.10 0.22
Carbon (C) 0.03
Manganese (Mn) 2.00
Silicon (Si) 1.00
Sulfur (S) 0.015
Phosphorus (P) 0.035

Mechanical properties

Property Value
Tensile Strength (UTS) 650 – 880 MPa (94 – 128 ksi)
Yield strength (0.2% Proof Strength) ≥450 MPa (65 ksi)
Stretching ≥25%
Hardness (Max) 270 HB
Impact resistance (Charpy V-Notch, 20°C) 100 J (74 ft.lb)

Physical properties

Property Value
Density 7.8 g/cm³
Heat capacity (20°C) 500 J/kg K
Coefficient of thermal expansion (20 – 100°C) 13.0 x 10⁻⁶ K⁻¹
Thermal conductivity (20°C) 15 W/m K
Electrical resistivity (20°C) 0.80 Ω mm²/m
Modulus of elasticity (20°C) 200 GPa

Heat treatments

  • Solubilization: 1020 – 1100°C with rapid cooling in water.
  • Hot forming: The optimum temperature for hot plastic deformation is between 950 and 1200°C.
  • Cold Forming: Can be cold worked, but requires higher machining forces than austenitic stainless steels.

Available formats

F51 DUPLEX stainless steel S31803 is available in the following shapes:


Industrial applications

Thanks to its high mechanical strength and corrosion resistance, DUPLEX F51 S31803 is widely used in the following sectors:

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