Alloy C22, UNS N06022, 2.4602, Hastelloy® C22 - nickel alloy

Alloy C22, UNS N06022, 2.4602, Hastelloy® C-22 - nickel alloy according to ASTM B 574-18 and DIN 17750:2021

Alloy C22, 2.4602, Hastelloy® C-22 – description

Alloy C-22 (N06022) is a Ni-Cr-Mo alloy developed in 1985 to achieve better thermal stability than Alloy C-276 and better chloride-induced localized corrosion and stress-corrosion cracking resistance than Alloy C-4. Because it was recognized that molybdenum and tungsten had an opposing role to that of chromium in reducing versus oxidizing acid environments, Alloy C-22 was developed with the proper balance of both elements to achieve versatility in a wide range of corrosive environments.

Applications

Alloy C-22 is used in acetic acid production, cellophane manufacturing, chlorination systems, complex acid mixtures, electro-galvanizing rolls, expansion bellows, flue gas scrubber systems, hydrogen fluoride scrubber systems, geothermal wells, incineration scrubber systems, nuclear fuel reprocessing, pesticide production, phosphoric acid production, pickling systems, plate heat exchangers, selective leaching systems, sulfur dioxide cooling towers, sulfonation systems, tubular heat exchangers, and weld overlays for valves.

Alloy C22, Hastelloy® C-22 - physical and mechanical properties

Room temperature physical properties:

• Density: 8.7 g/cm³
• Melting temperature: 1357-1400°C

High-temperature Coefficient of thermal expansion, from 20°C to:

• 100°C: 12.4 μm/m⋅K
• 300°C: 12.6 μm/m⋅K
• 400°C: 13.1 μm/m⋅K
• 500°C: 13.7 μm/m⋅K
• 600°C: 14.3 μm/m⋅K
• 700°C: 14.9 μm/m⋅K
• 800°C: 15.5 μm/m⋅K
• 900°C: 15.9 μm/m⋅K

High-temperature Specific heat capacity:

• 0°C: 414 J/kg⋅K
• 100°C: 423 J/kg⋅K
• 200°C: 444 J/kg⋅K
• 300°C: 460 J/kg⋅K
• 400°C: 476 J/kg⋅K
• 500°C: 485 J/kg⋅K
• 600°C: 514 J/kg⋅K

High-temperature Thermal diffusivity:

• 20°C: 2.7 10^–6⋅m²/s
• 100°C: 3.0 10^–6⋅m²/s
• 200°C: 3.5 10^–6⋅m²/s
• 300°C: 3.9 10^–6⋅m²/s
• 400°C: 4.2 10^–6⋅m²/s
• 500°C: 4.6 10^–6⋅m²/s
• 600°C: 4.8 10^–6⋅m²/s

High-temperature Thermal conductivity:

• 20°C: 10.1 W/m · K
• 100°C: 11.1 W/m · K
• 200°C: 13.4 W/m · K
• 300°C: 15.5 W/m · K
• 400°C: 17.5 W/m · K
• 500°C: 19.5 W/m · K
• 600°C: 21.3 W/m · K

High-temperature Electrical resistivity:

• 20°C: 1.14 μΩ·m
• 200°C: 1.24 μΩ·m
• 400°C: 1.26 μΩ·m
• 600°C: 1.28 μΩ·m

High-temperature Elastic modulus:

• 20°C: 206 GPa
• 200°C: 197 GPa
• 300°C: 191 GPa
• 400°C: 185 GPa
• 500°C: 179 GPa
• 600°C: 174 GPa
• 700°C: 168 GPa
• 800°C: 160 GPa
• 900°C: 152 GPa
• 1000°C: 144 GPa

Tensile properties of Alloy 2.4602 plates after tempering designated as F69 according to DIN 17750:2021:

• Yield strength: >310 MPa
• Tensile strength: >690 MPa
• Elongation: >45 %
• Hardness HBW: >240

Typical tensile properties of solution heat treated Hastelloy® C-22 sheets (0.71-3.2mm) according to the producer:

• 20°C:
  • Yield strength: 407 MPa
  • Tensile strength: 800 MPa
  • Elongation: 57 %
• 316°C:
  • Yield strength: 290 MPa
  • Tensile strength: 676 MPa
  • Elongation: 62 %
• 427°C:
  • Yield strength: 28 MPa
  • Tensile strength: 655 MPa
  • Elongation: 67 %
• 538°C:
  • Yield strength: 276 MPa
  • Tensile strength: 627 MPa
  • Elongation: 61 %
• 649°C:
  • Yield strength: 248 MPa
  • Tensile strength: 586 MPa
  • Elongation: 65 %
• 760°C:
  • Yield strength: 241 MPa
  • Tensile strength: 524 MPa
  • Elongation: 63 %

Typical tensile properties of solution heat treated Hastelloy® C-22 plates (6.4-19mm) according to the producer:

• 20°C:
  • Yield strength: 372 MPa
  • Tensile strength: 786 MPa
  • Elongation: 62 %
  • Elastic modulus: 206 GPa
• 316°C:
  • Yield strength: 248 MPa
  • Tensile strength: 655 MPa
  • Elongation: 68 %
  • Elastic modulus: 190 GPa
• 427°C:
  • Yield strength: 241 MPa
  • Tensile strength: 634 MPa
  • Elongation: 68 %
• 538°C:
  • Yield strength: 234 MPa
  • Tensile strength: 607 MPa
  • Elongation: 67 %
  • Elastic modulus: 177 GPa
• 649°C:
  • Yield strength: 221 MPa
  • Tensile strength: 572 MPa
  • Elongation: 69 %
• 760°C:
  • Yield strength: 214 MPa
  • Tensile strength: 534 MPa
  • Elongation: 68 %

Typical tensile properties of solution heat treated Hastelloy® C-22 bars (13-50mm) according to the producer:

• 20°C:
  • Yield strength: 359 MPa
  • Tensile strength: 765 MPa
  • Elongation: 70 %
• 316°C:
  • Yield strength: 234 MPa
  • Tensile strength: 634 MPa
  • Elongation: 79 %
• 427°C:
  • Yield strength: 214 MPa
  • Tensile strength: 614 MPa
  • Elongation: 79 %
• 538°C:
  • Yield strength: 200 MPa
  • Tensile strength: 579 MPa
  • Elongation: 80 %
• 649°C:
  • Yield strength: 193 MPa
  • Tensile strength: 552 MPa
  • Elongation: 80 %
• 760°C:
  • Yield strength: 200 MPa
  • Tensile strength: 496 MPa
  • Elongation: 77 %

Impact strength of solutioned Hastelloy® C-22:

• -195°C: 353 J
• 20°C: 351 J

Corrosion behaviour

Alloy C-22 has great corrosion resistance in oxidizing environment and has outstanding resistance to pitting, crevice corrosion and stress-corrosion cracking. It effectively resists oxidizing aqueous media, including wet chlorine and mixtures containing nitric acid or oxidizing acids with chloride ions. The alloy is particularly well-suited for environments with varying reducing and oxidizing conditions in process streams, making it versatile for applications where such conditions are present or in multipurpose plants.

Pitting corrosion in chloride environments - very good resistance. The critical pitting temperature in 6% FeCl₃ for 24 h period is 70°C. For 11.5% H₂SO₄ + 1.2% HCl + 1% FeCl₃ + 1% CuCl₂ the temperature is 120°C.

Stress-corrosion craking in chloride environments - very good resistance. The tests in boiling 45% magnesium chloride (according to ASTM G 36) has shown no cracking after 1008 h of testing.

Stress-corrosion craking in other environments - good resistance. Tests with two-point bend samples show cracks after 1000h of testing in 1%, 204°C HCl and no cracks after 12 months of testing in 4.7%, 204°C ZnBr2 nor 43%, 204°C CaBr₂

Corrosion rate in other specific environments:

• Acetic acid (CH₃COOH) 99%, boiling: 0 mm/year;
• Ferric chloride (FeCl₃) 10%, boiling: 0.025 mm/year;
• Formic acid (CH₂O₂) 88%, boiling: 0.0125 mm/year;
• Hydrochloric acid (HCl) 1%, boiling: 0.075 mm/year;
• ^ 1,5%, boiling: 0.35 mm/year;
• ^ 2%°C, at 90°C: 0 mm/year;
• ^ 2%, boiling: 1.525 mm/year;
• ^ 2,5%°C, at 90°C: 0.0125 mm/year;
• ^ 2,5%, boiling: 3.525 mm/year;
• ^ 10%, boiling: 10 mm/year;
• ^ 1% + 42g/L Fe₂(SO₄)₃°C, at 93°C: 0.05 mm/year;
• ^ 5% + 42g/L Fe₂(SO₄)₃°C, at 66°C: 0.05 mm/year;
• ^ 5% + 2% HF°C, at 70°C: 1.475 mm/year;
• Hydrofluoric acid (HF) 2%°C, at 70°C: 0.225 mm/year;
• ^ 5%°C, at 70°C: 0.35 mm/year;
• Phosphorus pentoxide (P₂O₅) 38%°C, at 85°C: 0.05 mm/year;
• ^ 44%°C, at 116°C: 0.525 mm/year;
• ^ 52%°C, at 116°C: 0.275 mm/year;
• ^ 38% + 200 ppm Cl°C, at 85°C: 0.025 mm/year;
• ^ 38% + 2% HF°C, at 85°C: 0.175 mm/year;
• Nitric acid (HNO₃) 10%, boiling: 0.0125 mm/year;
• ^ 65%, boiling: 3.35 mm/year;
• ^ 5% + 6% HF°C, at 60°C: 1.225 mm/year;
• ^ 5% + 25% H₂SO₄ + 4% NaCl, boiling: 0.3 mm/year;
• ^ 5% + 1% HCl, boiling: 0.0125 mm/year;
• ^ 5% + 2.5% HCl, boiling: 0.05 mm/year;
• ^ 9% + 15.8% HCl°C, at 52°C: 0.1 mm/year;
• Sulfuric acid (H₂SO₄) 2%°C, at 66°C: 0 mm/year;
• ^ 2%, boiling: 0.125 mm/year;
• ^ 5%°C, at 79°C: 0.0125 mm/year;
• ^ 5%, boiling: 0.225 mm/year;
• ^ 10%, boiling: 0.3 mm/year;
• ^ 20%°C, at 66°C: 0.0125 mm/year;
• ^ 20%°C, at 79°C: 0.025 mm/year;
• ^ 20%, boiling: 0.825 mm/year;
• ^ 30%°C, at 66°C: 0.0125 mm/year;
• ^ 30%°C, at 79°C: 0.075 mm/year;
• ^ 30%, boiling: 1.6 mm/year;
• ^ 40%°C, at 38°C: 0.0125 mm/year;
• ^ 40%°C, at 66°C: 0.0125 mm/year;
• ^ 40%°C, at 79°C: 0.225 mm/year;
• ^ 50%°C, at 38°C: 0.0125 mm/year;
• ^ 50%°C, at 66°C: 0.025 mm/year;
• ^ 50%°C, at 79°C: 0.4 mm/year;
• ^ 60%°C, at 38°C: 0.0125 mm/year;
• ^ 70%°C, at 38°C: 0 mm/year;
• ^ 80%°C, at 38°C: 0 mm/year;
• ^ 5% + 0.1% HCl, boiling: 0.65 mm/year;
• ^ 5% + 0.5% HCl, boiling: 1.525 mm/year;
• ^ 10% + 1% HCl°C, at 70°C: 0.0125 mm/year;
• ^ 10% + 1% HCl°C, at 90°C: 2.35 mm/year;
• ^ 10% + 1% HCl, boiling: 5.625 mm/year;
• ^ 10% + 2% HF, boiling: 0.725 mm/year;
• ^ 25% + 200 ppm Cl^-°C, at 70°C: 0.275 mm/year;
• ^ 25% + 200 ppm Cl^-, boiling: 5.375 mm/year;
• ^ 12% + 1.2% HCl + 1% FeCl₃ + 1% CuCl₂, boiling: 0.075 mm/year;
• ^ 23% + 1.2% HCl + 1% FeCl₃ + 1% CuCl₂, boiling: 0.2 mm/year;
• ^ 50% + 42g/L Fe₂(SO₄)₃ (ASTM G 28A), boiling: 1 mm/year;
• Phosphoric acid (H₃PO₄) 108%, at 280°C: 2.6 mm/year;
• ^ 112%, at 280°C: 3.9 mm/year;
• ^ 112%, at 280°C: 3.9 mm/year;

Weldability

Alloy C-22 has good weldability. It is used as a universal weld filler metaldue to its resistance to corrosion in weldments. For example, it has been used successfully to refurbish corroded welds in an alloy C-276 pulp and paper mill bleach-mixing device. It is included in weldability group 43 (ISO 15608).

Heat treatment, working and machining

Recommended working and heat treatment parameters:

• Forging: 1232-954 °C
• Solution-treatment: 1120±14 °C, 30 min, WQ

Forging - alloy can be hot forged, rolled, upset, extruded and formed. Moderate reductions and frequent re-heating are recommended for optimal results.

Cold working does not reduce the general corrosion resistance nor chloride-induced pitting resistance, but it can affect resistance to stress corrosion cracking. Post-working annealing is important for best corrosion performance.

Annealing involves heating to 1120°C and water quenching (thin pieces can be rapid air cooled). A hold time at the annealing temperature of 10 to 30 minutes is recommended, with thicker structures requiring the full 30 minutes. Annealing is essential after hot forming operations and any cold forming that results in an outer fiber elongation of 7% or more.

We deliver this steel alloy as:

• Rod, bar, wire, forging according to ASTM B 574 / ASME SB-574, ASMT B 564 / ASME SB-564, DIN 17752
• Plates, strips and sheets according to ASTM B 575 / ASME SB-575, DIN 17750
• Welded pipes according to ASTM B 619 / ASME SB-619
• Seamless pipes according to ASTM B 622 / ASME SB-622
• Materials for oil field equipment according to NACE MR-01-75

Replacements, equivalents and other designations:

Alloy C22, Bohler L022, Bohler L328 VMR, Coralloy 22, Junkeralloy C22S, Nistelle C-22, Nistelle C-22C, Hastelloy® C-22, Hastelloy® C-22HS, Haynes® 622 alloy, Phyweld® 22, UR 22 ArcelorMittal, H06022, NS3308, 2.4602, NiCr21Mo14W, Alloy 22, N06022, NW6022, NiCr21Mo13Fe4W2, AMS 5388, AMS 5389, AMS 5530, AMS 5750, ASTM A 474 / ASME SA-494, ASTM A 494 Grade CX2MW, ASTM B 366 (CRHC22) / ASME SB-366 (CRHC22), ASTM B 366 (WPHC22) / ASME SB-366 (WPHC22), ASTM B 462 (N06022) / ASME SB-462 (N06022), ASTM B 472 (N06022) / ASME SB-472 (N06022), ASTM B 474 (N06022) / ASME SB-474 (N06022), ASTM B 564 (N06022) / ASME SB-564 (N06022), ASTM B 574 (N06022) / ASME SB-574 (N06022), ASTM B 575 (N06022) / ASME SB-575 (N06022), ASTM B 619 (N06022) / ASME SB-619 (N06022), ASTM B 622 (N06022) / ASME SB-622 (N06022), ASTM B 626 (N06022) / ASME SB-626 (N06022), Inconel® alloy 22