Hastelloy C-22

Hastelloy C-22

Nickel (Ni) - 54.765 Balance
Chromium (Cr) - 21.25 Median
(20.0 Min - 22.5 Max)
Molybdenum (Mo) - 13.5 Median
(12.5 Min - 14.5 Max)
Iron (Fe) - 4.0 Median
(2.0 Min - 6.0 Max)
Tungsten (W) - 3.0 Median
(2.5 Min - 3.5 Max)
Cobalt (Co) - 2.5 Max
Other

Key

Nickel
Copper
Chromium
Aluminum
Molybdenum
Iron
Titanium
Manganese
Cobalt
Other
  • Nickel (Ni) 54.765 Balance
  • Chromium (Cr) 21.25 Median
    (20.0 Min - 22.5 Max)
  • Molybdenum (Mo) 13.5 Median
    (12.5 Min - 14.5 Max)
  • Iron (Fe) 4.0 Median
    (2.0 Min - 6.0 Max)
  • Tungsten (W) 3.0
  • Manganese (Mn) 0.5 Max
  • Cobalt (Co) 2.5 Max
  • Carbon (C) 0.015 Max
  • Vanadium (V) 0.35 Max
  • Silicon (Si) 0.08 Max
  • Phosphorus (P) 0.02 Max
  • Sulfur (S) 0.02 Max

UNS N06022

Hastelloy C-22 is a versatile nickel-chromium-molybdenum-tungsten alloy renowned for its exceptional resistance to a wide range of corrosive environments, including both oxidizing and reducing conditions. This alloy offers superb resistance to pitting, crevice corrosion, and stress corrosion cracking in harsh chemical environments containing chlorides, sulfuric acid, phosphoric acid, and other aggressive chemicals.

Its composition includes nickel, chromium, molybdenum, tungsten, and trace amounts of other elements. Hastelloy C-22 is commonly used in various applications across chemical processing, pollution control, pulp and paper, and pharmaceutical industries. Its properties make it well-suited for use in reactors, heat exchangers, scrubbers, and other equipment where corrosion resistance and reliability are paramount.

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Summary

  • Environment:
    Severe Environments: Hot Concentrated Acids & Chemicals
  • Temperature Limit:
    1250 °F / 677 °C
  • Ultimate Tensile (Typical):
    100 ksi / 689 mpa

Specifications & Technical Data

If your question isn’t answered below, download the complete technical data sheet here.

Specifications

  • Plate, Sheet & Strip: ASTM B575, ASME SB575
  • Rod & Bar: ASTM B574, ASME SB574
  • Seamless Pipe & Tube: ASTM B622, ASME SB622
  • Welded Pipe & Tube: ASTM B619, ASME SB619
  • Fittings: ASTM B366, ASME SB366
  • Forgings: ASTM B564, ASME SB564
  • Technischer Überwachungsverein (TÜV): Werkstoffblatt 479, Kennblatt 4535.00, Kennblatt 4536.00, Kennblatt 4534.01
  • Others: NACE MR0175

Physical Properties

Physical Property Imperial Units Metric Units
Density RT 0.314 lb/in3 RT 8.69 g/cm3
Melting Range 2475-2550°F 1357-1399°C
Electrical Resistivity RT 44.9 μ0hm.in RT 1.14 μ0hm.m
200°F 48.0 μ0hm.in 100°C 1.23 μ0hm.m
400°F 48.8 μ0hm.in 200°C 1.24 μ0hm.m
600°F 49.3 μ0hm.in 300°C 1.25 μ0hm.m
800°F 49.7 μ0hm.in 400°C 1.26 μ0hm.m
1000°F 50.1 μ0hm.in 500°C 1.27 μ0hm.m
600°C 1.28 μ0hm.m
Thermal Conductivity RT 69 btu.in/h.ft2.°F RT 10.1 W/m.°C
200°F 76 btu.in/h.ft2.°F 100°C 11.1 W/m.°C
400°F 94 btu.in/h.ft2.°F 200°C 13.4 W/m.°C
600°F 110 btu.in/h.ft2.°F 300°C 15.5 W/m.°C
800°F 125 btu.in/h.ft2.°F 400°C 17.5 W/m.°C
1000°F 139 btu.in/h.ft2.°F 500°C 19.5 W/m.°C
600°C 21.3 W/m.°C
Thermal Diffusivity RT 0.004 in2/s RT 0.027 cm2/s
200°F 0.005 in2/s 100°C 0.030 cm2/s
400°F 0.005 in2/s 200°C 0.035 cm2/s
600°F 0.006 in2/s 300°C 0.039 cm2/s
800°F 0.007 in2/s 400°C 0.042 cm2/s
1000°F 0.007 in2/s 500°C 0.046 cm2/s
600°C 0.048 cm2/s
Mean Coefficient of Thermal Expansion 75-200°F 6.9 μin/in. °F 24-100°C 12.4 μm/m.°C
75-400°F 6.9 μin/in. °F 24-200°C 12.4 μm/m.°C
75-600°F 7.0 μin/in. °F 24-300°C 12.6 μm/m.°C
75-800°F 7.4 μin/in. °F 24-400°C 13.1 μm/m.°C
75-1000°F 7.7 μin/in. °F 24-500°C 13.7 μm/m.°C
75-1200°F 8.1 μin/in. °F 24-600°C 14.3 μm/m.°C
75-1400°F 8.5 μin/in. °F 24-700°C 14.9 μm/m.°C
75-1600°F 8.8 μin/in. °F 24-800°C 15.5 μm/m.°C
75-1800°F 9.0 μin/in. °F 24-900°C 15.9 μm/m.°C
Specific Heat 100°F 0.098 Btu/lb.°F 50°C 414 J/kg.°C
200°F 0.101 Btu/lb.°F 100°C 423 J/kg.°C
400°F 0.106 Btu/lb.°F 200°C 444 J/kg.°C
600°F 0.111 Btu/lb.°F 300°C 460 J/kg.°C
800°F 0.114 Btu/lb.°F 400°C 476 J/kg.°C
1000°F 0.118 Btu/lb.°F 500°C 485 J/kg.°C
600°C 514 J/kg.°C
Dynamic Modulus of Elasticity RT 29.9 x 106 psi RT 206 GPa
200°F 29.4 x 106 psi 200°C 197 GPa
400°F 28.5 x 106 psi 300°C 191 GPa
600°F 27.6 x 106 psi 400°C 185 GPa
800°F 26.6 x 106 psi 500°C 179 GPa
1000°F 25.7 x 106 psi 600°C 174 GPa
1200°F 24.8 x 106 psi 700°C 168 GPa
1400°F 23.6 x 106 psi 800°C 160 GPa
1600°F 22.4 x 106 psi 900°C 152 GPa
1800°F 21.1 x 106 psi 1000°C 144 GPa
Melting Range 2475 – 2550°F 1357 – 1399 °C

RT= Room Temperature

Mechanical Properties

Tensile Strength & Elongation
Form Thickness/ Bar Diameter Test Temperature 0.2% Offset Yield Strength Ultimate Tensile Strength Elongation
in. mm. °F °C ksi MPa ksi MPa %
Sheet 0.028-0.125 0.7-3.2 RT RT 59 407 116 800 57
Sheet 0.028-0.125 0.7-3.2 200 93 54 372 110 758 58
Sheet 0.028-0.125 0.7-3.2 400 204 44 303 102 703 57
Sheet 0.028-0.125 0.7-3.2 600 316 42 286 98 676 62
Sheet 0.028-0.125 0.7-3.2 800 427 41 283 95 655 67
Sheet 0.028-0.125 0.7-3.2 1000 538 40 276 91 627 61
Sheet 0.028-0.125 0.7-3.2 1200 649 36 248 85 586 65
Sheet 0.028-0.125 0.7-3.2 1400 760 35 241 76 524 63
Plate 0.25-0.75 6.4-19.1 RT RT 54 372 114 786 62
Plate 0.25-0.75 6.4-19.1 200 93 49 338 107 738 65
Plate 0.25-0.75 6.4-19.1 400 204 41 283 98 676 66
Plate 0.25-0.75 6.4-19.1 600 316 36 248 95 655 68
Plate 0.25-0.75 6.4-19.1 800 427 35 241 92 634 68
Plate 0.25-0.75 6.4-19.1 1000 538 34 234 88 607 67
Plate 0.25-0.75 6.4-19.1 1200 649 32 221 83 572 69
Plate 0.25-0.75 6.4-19.1 1400 760 31 214 76 524 68
Bar 0.5-2.0 12.7-50.8 RT RT 52 359 111 765 70
Bar 0.5-2.0 12.7-50.8 200 93 45 310 105 724 73
Bar 0.5-2.0 12.7-50.8 400 204 38 262 96 662 74
Bar 0.5-2.0 12.7-50.8 600 316 34 234 92 634 79
Bar 0.5-2.0 12.7-50.8 800 427 31 214 89 614 79
Bar 0.5-2.0 12.7-50.8 1000 538 29 200 84 579 80
Bar 0.5-2.0 12.7-50.8 1200 649 28 193 80 552 80
Bar 0.5-2.0 12.7-50.8 1400 760 29 200 72 496 77

Values are averages from numerous tests
RT= Room Temperature

Impact Strength
Test Temperature Impact Strength
°F °C ft-lbf J
RT RT 419 568
-320 -196 346 469

Impact strengths were generated using Charpy V-notch samples, machined from mill annealed plate.
RT= Room Temperature

Hardness
Form Hardness, HRBW Typical ASTM Grain Size
Sheet 88 3.5 – 5.5
Plate 88 0 – 4.5
Bar 84 1 – 3.5

All samples tested in solution-annealed condition.
HRBW = Hardness Rockwell “B”, Tungsten Indentor.

Corrosion Resistance – Hydrobromic Acid

Hydrobromic Acid Corrosion Rate of C-22 (mm/y)
Conc. Wt. % 50°F 75°F 100°F 125°F 150°F 175°F 200°F 225°F Boiling
10°C 24°C 38°C 52°C 66°C 79°C 93°C 107°C
2.5 0.02
5 0.01 0.76
7.5 0.01 0.45
10 0.01 1.50
15 0.01 <0.01 0.88
20 0.01 0.46 0.8
25 <0.01 0.20 0.29 0.58 0.97
30 0.11 0.23 0.29 0.59 1.12
40 0.07 0.13 0.21 0.34 0.66

All corrosion rates are in millimeters per year (mm/y); to convert to mils (thousandths of an inch) per year, divide by 0.0254.
Data are from Corrosion Laboratory Jobs 15-02, 27-02, and 37-02.
All tests were performed in reagent grade acids under laboratory conditions; field tests are encouraged prior to industrial use.

Iso-Corrosion Diagram for C-22® Alloy in Hydrobromic Acid

Iso-Corrosion Diagram for C-22® Alloy in Hydrobromic Acid

 

Corrosion Resistance – Hydrochloric Acid

Hydrochloric Acid Corrosion Rate of C-22 (mm/y)
Conc. Wt. % 50°F 75°F 100°F 125°F 150°F 175°F 200°F 225°F Boiling
10°C 24°C 38°C 52°C 66°C 79°C 93°C 107°C
1 0.01 0.06
1.5
2
2.5
3
3.5
4
4.5
5 <0.01 0.44 1.44 3.02 8.99
7.5
10 0.01 0.28 0.98 1.99 4.39 11.68
15 0.98 1.91 11.02
20 0.20 0.32 0.90 1.72 3.38 9.73

All corrosion rates are in millimeters per year (mm/y); to convert to mils (thousandths of an inch) per year, divide by 0.0254. Data are from Corrosion Laboratory Jobs 442-82 and 176-83. All tests were performed in reagent grade acids under laboratory conditions; field tests are encouraged prior to industrial use.

Iso-Corrosion Diagram for C-22® Alloy in Hydrochloric Acid

Iso-Corrosion Diagram for C-22® Alloy in Hydrochloric Acid

 

Corrosion Resistance – Nitric Acid

Nitric Acid Corrosion Rate of C-22 (mm/y)
Conc. Wt. % 50°F 75°F 100°F 125°F 150°F 175°F 200°F 225°F Boiling
10°C 24°C 38°C 52°C 66°C 79°C 93°C 107°C
10 <0.01 0.01 0.01
20 0.01 0.02 0.06
30 0.01 0.02 0.13
40 0.02 0.03 0.09 0.26
50 0.05 0.14 0.33 0.59
60 0.06 0.08 0.19 0.57 1.09
70 0.05 0.11 0.33 0.71 2.53

All corrosion rates are in millimeters per year (mm/y); to convert to mils (thousandths of an inch) per year, divide by 0.0254. Data are from Corrosion Laboratory Jobs 443-82 and 47-04. All tests were performed in reagent grade acids under laboratory conditions; field tests are encouraged prior to industrial use.

Iso-Corrosion Diagram for C-22® Alloy in Nitric Acid

Iso-Corrosion Diagram for C-22® Alloy in Nitric Acid

 

Corrosion Resistance – Phosphoric Acid

Phosphoric Acid Corrosion Rate of C-22 (mm/y)
Conc. Wt. % 50°F 75°F 100°F 125°F 150°F 175°F 200°F 225°F Boiling
10°C 24°C 38°C 52°C 66°C 79°C 93°C 107°C
50 0.07
60 0.08 0.16
65
70 0.07 0.13 0.23
75 0.05 0.12 0.19
80 0.06 0.12 0.16 0.25
85 0.07 0.12 0.20 0.66

All corrosion rates are in millimeters per year (mm/y); to convert to mils (thousandths of an inch) per year, divide by 0.0254. Data are from Corrosion Laboratory Jobs 443-82 and 47-04. All tests were performed in reagent grade acids under laboratory conditions; field tests are encouraged prior to industrial use.

Iso-Corrosion Diagram for C-22® Alloy in Phosphoric Acid

 

Corrosion Resistance – Sulfuric Acid

Sulfuric Acid Corrosion Rate of C-22 (mm/y)
Conc. Wt. % 75°F 100°F 125°F 150°F 175°F 200°F 225°F 250°F 275°F Boiling
24°C 38°C 52°C 66°C 79°C 93°C 107°C 121°C 135°C
1
2 0.01 0.13
3
4
5 <0.01 0.01 0.03 0.23
10 0.02 0.04 0.29
20 0.01 0.03 0.28 0.83
30 0.01 0.09 0.68 1.89
40 0.01 0.01 0.31 0.87 3.99
50 0.02 0.40 0.77 2.18 9.98
60 0.01 0.67 0.95 2.69 7.62
70 0.28 0.56 0.94 3.07 14.94
80 0.09 1.44 2.16 3.68 3.58
90 0.34 0.89 1.80 6.27 4.24
96 0.10 1.10

All corrosion rates are in millimeters per year (mm/y); to convert to mils (thousandths of an inch) per year, divide by 0.0254. Data are from Corrosion Laboratory Jobs 319-82, 445-82, and 19-14. All tests were performed in reagent grade acids under laboratory conditions; field tests are encouraged prior to industrial use.

Iso-Corrosion Diagram for C-22® Alloy in Sulfuric Acid

 

Corrosion Resistance – Reagent Grade Solutions

Chemical Concentration 100°F 125°F 150°F 175°F 200°F Boiling
wt. % 38°C 52°C 66°C 79°C 93°C
Acetic Acid 99 0
Formic Acid 88 <0.01
Hydrobromic Acid
2.5 0.02
5 0.76
7.5 0.01
10 0.01
15 0.01 <0.01 0.88
20 0.01 0.46 0.80
25 <0.01 0.20 0.29 0.58
30 0.11 0.23 0.29 0.59
40 0.07 0.13 0.21 0.34
Hydrochloric Acid
1 0.01 0.06
5 <0.01 0.44
7.5
10 0.01 0.28 0.98
15
20 0.20 0.32 0.90
Hydrofluoric Acid*
5 0.04 0.15 0.47 0.58
10 0.09 0.33 0.64 0.78
20 0.22 0.53 0.95 1.65
Nitric Acid
10 <0.01 0.01 0.01
20 0.01 0.02 0.06
30 0.01 0.0.2 0.13
40 0.02 0.09 0.26
50 0.14 0.59
60 0.06 0.19 1.09
65
70 0.05 0.33 2.53
Phosphoric Acid
50 0.07
60 0.16
70 0.23
75 0.19
80 0.25
85 0.66
Sulfuric Acid
10 0.02 0.04 0.29
20 0.01 0.03 0.28 0.83
30 0.01 0.09 0.68
40 0.01 0.31 0.87
50 0.02 0.40 0.77
60 0.67 0.95
70 0.28 0.56 0.94
80 1.44 2.16
90 0.34 0.89 1.80
96 0.10 1.10

*Hydrofluoric acid can also induce internal attack of nickel alloys; these values represent only external attack.

Resistance to Pitting & Crevice Corrosion

Test in 6 wt.% ferric chloride (ASTM Standard G 48)
Alloy Critical Pitting Temperature in Acidified 6% FeCl3 Critical Crevice Temperature in Acidified 6% FeCl3
°F °C °F °C
316L 59 15 32 0
254SMO 140 60 86 30
625 212 100 104 40
C-276 >302 >150 131 55
C-22® >302 >150 176 80

Resistance to Stress Corrosion Cracking

Test in Boiling 45% magnesium chloride (ASTM Standard G 36)
Alloy Time to Cracking
316L 2 h
254SMO 24 h
625 No Cracking in 1,008 h
C-276 No Cracking in 1,008 h
C-22® No Cracking in 1,008 h

Resistance to Seawater Crevice Corrosion

Tested in seawater at 29°C, plus or minus 3°C for 180 days
Alloy Quiescent Flowing
No. of Sites Attacked Maximum Depth of Attack, mm No. of Sites Attacked Maximum Depth of Attack, mm
316L A:2, B:2 A:1.33, B:2.27 A:2, B:2 A:0.48, B:0.15
254SMO A:2, B:2 A:0.76, B:1.73 A:2, B:2 A:0.01, B:<0.01
625 A:1, B:2 A:0.18, B:0.04 A:2, B:2 A:<0.01, B:<0.01
C-276 A:1, B:1 A:0.10, B:0.13 A:0, B:0 A:0, B:0
C-22® A:0, B:0 A:0, B:0 A:0, B:0 A:0, B:0

Data was generated as part of a U.S. Navy study at the LaQue Laboratories in Wrightsville Beach, North Carolina (and published by D.M. Aylor et al, Paper No. 329, CORROSION 99, NACE International, 1999).

Corrosion Resistance of Welds

Chemical Concentration Temperature Corrosion Rate
wt. % °F °C Weld Metal Wrought Base Metal
mpy mm/y mpy mm/y
H2SO4 30 150 66 0.6 0.02 0.4 0.01
H2SO4 50 150 66 9.3 0.24 0.8 0.02
H2SO4 70 150 66 10.3 0.26 11 0.28
H2SO4 90 150 66 18.5 0.47 13.4 0.34
HCI 5 100 38 <0.1 <0.01 <0.1 <0.01
HCI 10 100 38 <0.1 <0.01 0.4 0.01
HCI 15 100 38 11.1 0.28 9.4 0.24
HCI 20 100 38 10.2 0.26 7.9 0.20
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