Nickel and nickel alloys · Alloy 20 / Incoloy 20 / UNS N08020 / 2.4660

Superalloy Alloy 20 (UNS N08020): Engineering Specifications and Product Range

Engineering Specifications of Incoloy 20 (Alloy 20)

Delivery FormsParameterValue
Main Specifications2.4660
Main Specifications2.4660
International DesignationsSheet, plate, strip, bar, flat bar, hexagon, wire, tube, forged blanksAlloy 20
International DesignationsSheet, plate, strip, bar, flat bar, hexagon, wire, tube, forged blanksCarpenter 20Cb-3
International DesignationsSheet, plate, strip, bar, flat bar, hexagon, wire, tube, forged blanksIncoloy 20
Main SpecificationsNiCr20CuMo
Main SpecificationsNiCr20CuMo
Main SpecificationsB 366
Main SpecificationsB 366
Main SpecificationsSB 366
Main SpecificationsSB 366
Main SpecificationsB 462
Main SpecificationsB 462
Main SpecificationsSB 462
Main SpecificationsSB 462
Main SpecificationsB 463
Main SpecificationsB 463
Main SpecificationsSB 463
Main SpecificationsSB 463
Main SpecificationsB 464
Main SpecificationsB 464
Main SpecificationsSB 464
Main SpecificationsSB 464
Main SpecificationsB 468
Main SpecificationsB 468
Main SpecificationsSB 468
Main SpecificationsSB 468
Main SpecificationsB 471
Main SpecificationsB 471
Main SpecificationsSB 471
Main SpecificationsSB 471
Main SpecificationsB 472
Main SpecificationsB 472
Main SpecificationsSB 472
Main SpecificationsSB 472
Main SpecificationsB 473
Main SpecificationsB 473
Main SpecificationsSB 473
Main SpecificationsSB 473
Main SpecificationsB 474
Main SpecificationsB 474
Main SpecificationsSB 474
Main SpecificationsSB 474
Main SpecificationsB 475
Main SpecificationsB 475
Main SpecificationsSB 475
Main SpecificationsSB 475
Main SpecificationsB 729
Main SpecificationsB 729
Main SpecificationsSB 729
Main SpecificationsSB 729
Main SpecificationsB 751
Main SpecificationsB 751
Main SpecificationsSB 751
Main SpecificationsSB 751
Main SpecificationsB 775
Main SpecificationsB 775
Main SpecificationsSB 775
Main SpecificationsSB 775
Main SpecificationsB 829
Main SpecificationsB 829
Main SpecificationsSB 829
Main SpecificationsSB 829
International DesignationsSheet, plate, strip, bar, flat bar, hexagon, wire, tube, forged blanksNicrofer 3620 Nb
International DesignationsSheet, plate, strip, bar, flat bar, hexagon, wire, tube, forged blanksUNS N08020
Main SpecificationsSheet, plate, strip, bar, flat bar, hexagon, wire, tube, forged blanksASME
Main SpecificationsSheet, plate, strip, bar, flat bar, hexagon, wire, tube, forged blanksASTM
Main SpecificationsSheet, plate, strip, bar, flat bar, hexagon, wire, tube, forged blanksDIN / W.Nr.

Alloy 20, classified as an austenitic nickel-iron-chromium superalloy, is developed for operation in extreme corrosive environments. Alloying with copper (Cu) and molybdenum (Mo) in combination with niobium (Nb) stabilization provides the material with exceptional resistance to general and localized corrosion, especially in sulfuric acid environments where standard stainless steels are subject to rapid degradation.

Chemical Composition of Alloy 20 (%)

NiCrCuMoNb+TaCMnSiFe
32.0-38.019.0-21.03.0-4.02.0-3.08*C-1.0<0.07<2.0<1.0Balance

Mechanical Properties (typical values at 20°C)

Tensile Strength (Rm)ParameterValue
Yield Strength (Rp0.2)620 MPa / 90 ksi300 MPa / 45 ksi
Elongation after fracture (A)620 MPa / 90 ksi40%

Corrosion Resistance and Application Areas

EV Group China engineering technologists recommend the use of Alloy 20 in environments containing sulfuric, phosphoric, and other aggressive acids. The presence of molybdenum ensures high resistance to pitting and crevice corrosion. Niobium stabilization minimizes carbide precipitation in the heat-affected zone of the weld seam, which is a critical factor for maintaining the corrosion resistance of welded structures operating in chemical reactors.

Key Operational Advantages:

  • Exceptional corrosion resistance in hot concentrated sulfuric acid solutions.
  • Resistance to intergranular corrosion in the post-weld condition due to niobium stabilization.
  • High resistance to chloride stress corrosion cracking (SCC).
  • Excellent weldability using standard methods, including TIG/GTAW, MIG/GMAW, and Plasma Arc Welding (PAW).

Typical Application Industries:

  • Chemical industry: production of sulfuric acid, phosphate fertilizers, synthetic fibers.
  • Pharmaceutical and food industry: reactors, pipelines, and tanks for technological processes.
  • Petrochemicals: installations for the synthesis of polymers and rubbers.
  • Energy and mechanical engineering: high-reliability heat exchangers operating in aggressive environments.