spore: profile
id: hastelloy-c22
spore_version: 0.2
family: nickel-alloys
name: Hastelloy C-22
abbreviation: C-22
role: corrosion-resistant structural alloy
category: metals
type: nickel-superalloys
summary: |
  Hastelloy C-22 (UNS N06022, W.Nr. 2.4602) is a nickel-chromium-molybdenum-tungsten alloy with nickel as the balance, 20.0 to 22.5 % chromium, 12.5 to 14.5 % molybdenum and 2.5 to 3.5 % tungsten. In the solution-annealed condition it has a density of 8.69 g/cm3, a melting range of 1357 to 1399 °C and a room-temperature yield strength of at least 310 MPa. It resists pitting and crevice attack in hot chloride solutions, and in a 180-day seawater crevice test it showed no attack. Its thermal conductivity is low, 10.1 W/(m·K) at 48 °C.
best_for: Resisting pitting and crevice corrosion in hot chloride, oxidizing and mixed acid environments, including seawater, in the solution-annealed condition
weakest_at: Long exposure at 593 to 760 °C, where mu phase forms on grain boundaries and ductility falls, and hot hydrochloric acid, which corrodes it at more than 10 mm/y when boiling
identity:
  formula: Ni balance, Cr 20.0 to 22.5, Mo 12.5 to 14.5, Fe 2.0 to 6.0, W 2.5 to 3.5 wt% (nickel-chromium-molybdenum-tungsten alloy, UNS N06022)
  source: hightemp-c22
  where: 'Type Analysis composition table: Molybdenum 12.5 to 14.5, Chromium 20.0 to 22.5, Iron 2.00 to 6.00, Tungsten 2.50 to 3.50, Nickel remainder (weight %)'
  designations:
    - system: UNS
      code: N06022
      source: zapp-c22
      where: Specifications table, row UNS (footnote 1, chemical composition)
    - system: EN
      code: '2.4602'
      source: zapp-c22
      where: Specifications table, row Material number
    - system: EN name
      code: NiCr21Mo14W
      source: zapp-c22
      where: Specifications table, row DIN-Code
    - system: DIN
      code: '17744'
      note: chemical composition standard
      source: zapp-c22
      where: Specifications table, row DIN, footnote 1 (chemical composition)
    - system: ASTM
      code: B-575
      note: sheet, plate and strip
      source: hightemp-c22
      where: Designation Codes, ASTM specifications list
    - system: ASTM
      code: B-574
      note: billet, rod and bar
      source: hightemp-c22
      where: Designation Codes, ASTM specifications list
    - system: ASTM
      code: B-619
      note: welded pipe and tube
      source: hightemp-c22
      where: Designation Codes, ASTM specifications list
    - system: ASTM
      code: B-622
      note: seamless pipe and tube
      source: hightemp-c22
      where: Designation Codes, ASTM specifications list
    - system: ASTM
      code: B-626
      note: welded and seamless tube
      source: hightemp-c22
      where: Designation Codes, ASTM specifications list
    - system: ASME
      code: SB-575
      note: sheet, plate and strip
      source: hightemp-c22
      where: Designation Codes, ASME specifications list
    - system: Trade name
      code: Hastelloy C-22
      note: also written Alloy C-22
      source: hightemp-c22
      where: Designation Codes, trade name line
tags:
  environments:
    - launch
  stresses:
    - chloride-corrosion
    - cryogenic-temperatures
  applications:
    - cryogenic-fuel
    - structures
properties:
  - benchmark: density
    label: Density, solution-annealed Hastelloy C-22
    value: 8.69
    unit: g/cm3
    scope: material
    conditions:
      temperature: 24 °C (75 °F)
      unit_in_source: 0.314 lb/in3 at 75 °F
      form: not stated in the table
    method: Average value printed in a table reproducing manufacturer (Haynes International) average physical properties
    status: ground
    source: hightemp-c22
    where: Average Physical Properties table, row Density, 24 °C, 8.69 g/cm(3)
  - benchmark: melting_point
    label: Melting range, Hastelloy C-22
    value: 1357
    value_high: 1399
    bound: range
    unit: °C
    scope: material
    conditions:
      unit_in_source: 2475 to 2550 °F
      pressure: not stated
    method: Melting range printed in a manufacturer-derived average physical properties table
    status: ground
    source: hightemp-c22
    where: Average Physical Properties table, row Melting Range, 1357 to 1399 °C
  - benchmark: elastic_modulus
    label: Dynamic modulus of elasticity at room temperature, heat-treated plate
    value: 206
    unit: GPa
    scope: material
    conditions:
      temperature: room temperature
      form: plate, heat-treated at 2050 °F (1121 °C) and rapid quenched
      unit_in_source: 29.9 x 10(6) psi
    method: Average dynamic modulus printed in a manufacturer-derived table, not a static tensile test
    status: ground
    source: hightemp-c22
    where: Average Dynamic Modulus of Elasticity table, row Room, 29.9 (206)
  - benchmark: thermal_conductivity
    label: Thermal conductivity at 48 °C
    value: 10.1
    unit: W/(m·K)
    scope: material
    conditions:
      temperature: 48 °C (118 °F)
      unit_in_source: 70 Btu-in/ft2-hr-°F
    method: Value printed in a manufacturer-derived thermal conductivity table
    status: ground
    source: hightemp-c22
    where: Thermal Conductivity table, row 118 °F / 48 °C, 10.1 W/m-K
  - benchmark: thermal_conductivity
    label: Thermal conductivity at 600 °C
    value: 21.3
    unit: W/(m·K)
    scope: material
    conditions:
      temperature: 600 °C (1112 °F)
      unit_in_source: 148 Btu-in/ft2-hr-°F at 1112 °F
    method: Value printed in a manufacturer-derived thermal conductivity table
    status: ground
    source: hightemp-c22
    where: Thermal Conductivity table, row 600 °C, 21.3 W/m-K
  - benchmark: specific_heat
    label: Specific heat capacity at room temperature
    value: 410
    unit: J/(kg·K)
    scope: material
    conditions:
      temperature: room temperature (footnote marked with an asterisk)
      unit_in_source: 410 J · kg-1 · K-1
    method: Value printed in a manufacturer datasheet physical properties box
    status: ground
    source: zapp-c22
    where: Physical properties box, row Specific heat, 410 [J · kg-1 · K-1]
  - benchmark: specific_heat
    label: Specific heat capacity at 50 °C
    value: 414
    unit: J/(kg·K)
    scope: material
    conditions:
      temperature: 50 °C
      unit_in_source: 0.098 Btu/lb-°F at 100 °F
    method: Value printed in the manufacturer product page physical properties table
    status: ground
    source: haynes-c22
    where: Physical Properties table, row Specific heat, 414 J/kg.°C at 50 °C
  - benchmark: cte
    label: Mean coefficient of thermal expansion, 24 to 93 °C
    value: 12.4
    unit: ppm/K
    scope: material
    conditions:
      temperature: 24 to 93 °C mean range
      unit_in_source: 12.4 X 10(-6) m/m-K
    method: Mean value printed in a manufacturer-derived expansion table
    status: ground
    source: hightemp-c22
    where: Mean Coefficient of Thermal Expansion table, row 24 to 93 °C, 12.4 X 10(-6) m/m-K
  - benchmark: cte
    label: Mean coefficient of thermal expansion, 24 to 760 °C
    value: 15.3
    unit: ppm/K
    scope: material
    conditions:
      temperature: 24 to 760 °C mean range
      unit_in_source: 15.3 X 10(-6) m/m-K
    method: Mean value printed in a manufacturer-derived expansion table
    status: ground
    source: hightemp-c22
    where: Mean Coefficient of Thermal Expansion table, row 24 to 760 °C, 15.3 X 10(-6) m/m-K
  - benchmark: electrical_resistivity
    label: Electrical resistivity at 24 °C
    value: 1.14
    unit: µΩ·m
    scope: material
    conditions:
      temperature: 24 °C (75 °F)
      unit_in_source: 1.14 microhm-m
    method: Value printed in a manufacturer-derived electrical resistivity table
    status: ground
    source: hightemp-c22
    where: Electrical Resistivity table, row 75 °F / 24 °C, 1.14 microhm-m
  - benchmark: yield_strength
    label: Yield strength Rp0.2 minimum, solution-annealed sheet up to 50 mm
    value: 310
    bound: lower
    unit: MPa
    scope: material
    conditions:
      temperature: room temperature
      temper: solution-annealed
      form: semi-finished sheet up to 50 mm
      measure: Rp0.2 minimum
    method: Minimum value printed in a manufacturer datasheet mechanical properties table
    status: ground
    source: zapp-c22
    where: Mechanical properties table, row RT, column Yield strength Rp 0.2 min. (MPa), 310
  - benchmark: yield_strength
    label: Yield strength Rp0.2 average, solution-treated sheet 0.028 to 0.125 in thick
    value: 403
    unit: MPa
    scope: material
    conditions:
      temperature: room temperature
      temper: solution heat-treated
      form: sheet 0.028 to 0.125 in (0.7 to 3.2 mm) thick
      unit_in_source: 58.5 ksi
    method: Average from numerous tests printed in a manufacturer-derived tensile data table
    status: ground
    source: hightemp-c22
    where: Tensile Data, Sheet 0.028 to 0.125 in thick, row Room, Yield 58.5 (403)
  - benchmark: yield_strength
    label: Yield strength Rp0.2 minimum at 200 °C, solution-annealed sheet up to 50 mm
    value: 225
    bound: lower
    unit: MPa
    scope: material
    conditions:
      temperature: 200 °C
      temper: solution-annealed
      form: semi-finished sheet up to 50 mm
      measure: Rp0.2 minimum
    method: Minimum value printed in a manufacturer datasheet mechanical properties table
    status: ground
    source: zapp-c22
    where: Mechanical properties table, row 200, column Yield strength Rp 0.2 min. (MPa), 225
  - benchmark: yield_strength
    label: Yield strength Rp0.2 minimum at 400 °C, solution-annealed sheet up to 50 mm
    value: 175
    bound: lower
    unit: MPa
    scope: material
    conditions:
      temperature: 400 °C
      temper: solution-annealed
      form: semi-finished sheet up to 50 mm
      measure: Rp0.2 minimum
    method: Minimum value printed in a manufacturer datasheet mechanical properties table
    status: ground
    source: zapp-c22
    where: Mechanical properties table, row 400, column Yield strength Rp 0.2 min. (MPa), 175
  - benchmark: ultimate_tensile_strength
    label: Tensile strength Rm at room temperature, solution-annealed sheet up to 50 mm
    value: 690
    value_high: 950
    bound: range
    unit: MPa
    scope: material
    conditions:
      temperature: room temperature
      temper: solution-annealed
      form: semi-finished sheet up to 50 mm
    method: Range printed in a manufacturer datasheet mechanical properties table
    status: ground
    source: zapp-c22
    where: Mechanical properties table, row RT, column Strength Rm (MPa), 690 to 950
  - benchmark: ultimate_tensile_strength
    label: Tensile strength average at room temperature, solution-treated sheet 0.028 to 0.125 in thick
    value: 802
    unit: MPa
    scope: material
    conditions:
      temperature: room temperature
      temper: solution heat-treated
      form: sheet 0.028 to 0.125 in (0.7 to 3.2 mm) thick
      unit_in_source: 116.3 ksi
    method: Average from numerous tests printed in a manufacturer-derived tensile data table
    status: ground
    source: hightemp-c22
    where: Tensile Data, Sheet 0.028 to 0.125 in thick, row Room, UTS 116.3 (802)
  - benchmark: elongation
    label: Elongation minimum at room temperature, solution-annealed sheet up to 50 mm
    value: 45
    bound: lower
    unit: '%'
    scope: material
    conditions:
      temperature: room temperature
      temper: solution-annealed
      form: semi-finished sheet up to 50 mm
      gauge_length: not stated
    method: Minimum value printed in a manufacturer datasheet mechanical properties table
    status: ground
    source: zapp-c22
    where: Mechanical properties table, row RT, column Expansion min. (%), 45
  - benchmark: elongation
    label: Elongation average at room temperature, solution-treated sheet 0.028 to 0.125 in thick
    value: 57
    unit: '%'
    scope: material
    conditions:
      temperature: room temperature
      temper: solution heat-treated
      form: sheet 0.028 to 0.125 in (0.7 to 3.2 mm) thick
      gauge_length: 2 in
    method: Average from numerous tests printed in a manufacturer-derived tensile data table
    status: ground
    source: hightemp-c22
    where: Tensile Data, Sheet 0.028 to 0.125 in thick, row Room, Elongation 57
  - benchmark: charpy_impact_energy
    label: Charpy V-notch impact energy at -196 °C, mill-annealed plate
    value: 469
    unit: J
    scope: material
    conditions:
      temperature: '-196 °C (-320 °F)'
      form: mill-annealed plate
      specimen: Charpy V-notch
      unit_in_source: 346 ft-lbf
    method: Value printed in a manufacturer product page impact property list
    status: ground
    source: haynes-c22
    where: Impact (Charpy V-notch, mill annealed plate), row -320 °F (-196 °C), 346 ft-lbf (469 J)
corrosion:
  - environment: Chloride solutions with ferric chloride (ASTM G 48 pitting and crevice test)
    headline: Hastelloy C-22 has a critical crevice temperature of 80 °C in acidified 6 % ferric chloride, and no pitting up to above 150 °C.
    effect: In the ASTM G 48 test (acidified 6 wt% FeCl3, 72 h), C-22 showed a critical pitting temperature above 150 °C and a critical crevice temperature of 80 °C, against 55 °C for C-276, 40 °C for alloy 625 and 0 °C for 316L.
    rating: low
    conditions:
      test: ASTM G 48, acidified 6 wt% FeCl3, 72 h
      unit_in_source: °F (°C) printed in pairs
    source: haynes-c22
    where: Pitting and crevice section, table of critical pitting and crevice temperatures
  - environment: Green Death and Yellow Death test solutions
    headline: C-22 resists pitting in the aggressive Yellow Death solution up to 150 °C and has a lowest pitting temperature of 120 °C in Green Death.
    effect: The Green Death solution (11.5 % H2SO4, 1.2 % HCl, 1 % FeCl3, 1 % CuCl2, 24 h) gave a lowest pitting temperature of 120 °C for C-22. In Yellow Death (4 % NaCl, 0.1 % Fe2(SO4)3, 0.021 M HCl, 24 h) it showed no pitting up to 150 °C, with a critical crevice temperature of 75 °C.
    rating: low
    conditions:
      test: Green Death and Yellow Death, 24 h each
      basis: manufacturer test data
    source: haynes-c22
    where: Pitting and crevice section, paragraphs on Green Death and Yellow Death
  - environment: Seawater, crevice test (U.S. Navy LaQue study)
    headline: In a 180-day seawater crevice test, C-22 showed no attacked crevice sites in quiescent or flowing seawater.
    effect: In a 180-day test at 29 °C ±3 °C, C-22 had zero attacked crevice sites in both quiescent and flowing seawater, while 316L had up to 2.27 mm of crevice depth in quiescent seawater and 254SMO 1.73 mm.
    rating: low
    conditions:
      temperature: 29 °C ±3 °C
      duration: 180 days
      basis: U.S. Navy LaQue study cited by the manufacturer
    source: haynes-c22
    where: Seawater crevice corrosion table, row C-22 (0 sites attacked in both columns)
  - environment: Hot hydrochloric acid (10 wt% HCl)
    headline: Hot hydrochloric acid attacks C-22 at a rate that rises steeply with temperature, reaching 11.68 mm/y at boiling for 10 % HCl.
    effect: Laboratory general corrosion rates for 10 % HCl were 0.98 mm/y at 150 °F (66 °C), 4.39 mm/y at 200 °F (93 °C) and 11.68 mm/y at boiling. The page notes that field tests are encouraged before industrial use.
    rating: severe
    conditions:
      unit_in_source: mm/y
      basis: reagent-grade acid, laboratory test
    source: haynes-c22
    where: Corrosion resistance section, Hydrochloric acid row, 10 % line (150 °F 0.98, 200 °F 4.39, boiling 11.68)
  - environment: Hot sulphuric acid (70 wt%)
    headline: Sulphuric acid at 70 % concentration corrodes C-22 at 0.28 mm/y at 150 °F and 14.94 mm/y at 250 °F.
    effect: General corrosion rates for 70 % H2SO4 were 0.28 mm/y at 150 °F (66 °C) and 14.94 mm/y at 250 °F (121 °C), so the alloy suits some sulphuric acid service only at lower temperatures or concentrations.
    rating: severe
    conditions:
      basis: reagent-grade acid, laboratory test
      unit_in_source: mm/y
    source: haynes-c22
    where: Corrosion resistance section, Sulfuric acid row, 70 % line (150 °F 0.28, 250 °F 14.94)
  - environment: Shuttle launch-site cryogenic supply line exposure
    headline: At the Space Shuttle launch site C-22 outperformed 304L stainless steel, which had failed by pitting, and was chosen for the bellows.
    effect: A launch-site alloy test found C-22 the best of all alloys tested. The paper says 304L at the launch site had failed by pitting. C-22 bellows were welded on site to the existing structure.
    rating: low
    conditions:
      environment: launch site, cryogenic supply lines, coastal exposure
      duration: not stated in the page
      basis: NASA test report MTB-325-87A, 23 August 1988, as summarized by the manufacturer
    source: haynes-shuttle-bellows
    where: Article text, paragraphs on the launch-site alloy evaluation and bellows installation
  - environment: Boiling chloride with stress (boiling 45 % MgCl2)
    headline: In boiling 45 % magnesium chloride, C-22 showed no stress corrosion cracking in 1008 h, while 316L cracked in 2 h.
    effect: In the U-bend test (ASTM G 36) in boiling 45 % MgCl2, 316L cracked in 2 h and 254SMO in 24 h, while C-22, alloy 625 and C-276 showed no cracking in 1008 h.
    rating: low
    conditions:
      test: ASTM G 36 U-bend, boiling 45 % MgCl2, 1008 h
    source: haynes-c22
    where: Stress corrosion cracking section, paragraph with the 1008 h U-bend test
risks:
  hazards:
    - text: 'Stanford Advanced Materials safety data sheet for Hastelloy C276 and C22: the solid is not classified as hazardous under 29 CFR 1910.1200. Grinding, melting or welding can produce dust or fume that is hazardous if inhaled or in contact with skin or eyes.'
      ghs: []
      source: stanford-sds-hastelloy
      where: Sections 2 (hazard identification) and 4 (first aid general measures)
    - text: Fine chips, turnings and dust from processing may be ignitable, and fire can release metal oxide fumes. The product does not present a fire hazard as shipped.
      ghs: []
      source: stanford-sds-hastelloy
      where: Section 5 Firefighting measures
    - text: 'Exposure limits printed on the same sheet: nickel 1 mg/m3 OSHA PEL and 1.5 mg/m3 ACGIH TLV; chromium 1 mg/m3 OSHA PEL and 0.5 mg/m3 ACGIH TLV; cobalt 0.1 mg/m3 OSHA PEL and 0.02 mg/m3 ACGIH TLV.'
      ghs: []
      source: stanford-sds-hastelloy
      where: Section 8 Exposure controls, table of exposure limits
  failure_risks:
    - mode: Mu phase precipitation and embrittlement after long exposure at 593 to 760 °C
      trigger: Service or heat treatment at 593 to 760 °C for long periods; the study tested 2000 h and 16000 h
      consequence: Mu phase forms on grain boundaries at all temperatures tested and, at higher temperatures, through the bulk. The abstract says strength rose somewhat with aging but ductility fell due to grain boundary precipitates and brittle intermetallics.
      severity: moderate
      source: summers-1999-c22
      where: Abstract
    - mode: Loss of stress corrosion resistance after cold work
      trigger: Cold forming above about 15 % deformation without a new solution anneal
      consequence: The datasheet says a new solution anneal is required after cold forming above 15 %, and the manufacturer page says cold work can affect stress corrosion cracking resistance.
      severity: moderate
      source: zapp-c22
      where: Processing instructions, paragraph on cold and hot forming
    - mode: Use above the code design limits
      trigger: Service above 427 °C under ASME B31.3 or Section III Class 1, or above 677 °C under ASME Section VIII
      consequence: The page gives the code limits but does not state the failure mode when they are exceeded.
      severity: low
      source: haynes-c22
      where: Section 7 Service Temperature Limits, table of ASME limits
  side_effects: []
  handling:
    - text: Solution anneal at 1105 to 1135 °C, then cool in water, compressed air or inert gas. The manufacturer page gives 1121 °C with a water quench, and air cooling is feasible for sections under 10 mm.
      source: zapp-c22
      where: Heat treatment section; haynes-c22 processing temperatures
    - text: Hot forming starts at 1232 °C and finishes at 954 °C, and the working range is narrow. The alloy work-hardens, so a new solution anneal is needed after cold forming above 15 %.
      source: zapp-c22
      where: Processing instructions
    - text: Welding is preferably done by TIG (WIG) or MIG, and the page says little heat should be introduced to keep corrosion resistance. Preheating or post-weld heat treatment are usually not required.
      source: zapp-c22
      where: Welding section
  mitigations: []
uses:
  - application: cryogenic-fuel
    device: Welded bellows in vacuum-jacketed cryogenic supply lines at the Space Shuttle launch site
    example: The launch-site lines were first 304L stainless steel, which failed by pitting. C-22 bellows were welded on site, and the report that chose C-22 (MTB-325-87A, 23 August 1988) found it the best of all alloys tested. Bellows for the fuel cell transfer line were also tested for fatigue (MTB-688-87, 2 December 1987) and far exceeded 304L.
    source: haynes-shuttle-bellows
    where: Article text, sections on the launch site and the fatigue testing; NASA test report references
  - application: cryogenic-fuel
    device: Bellows for repair of the LC-39B fuel cell servicing system (Space Shuttle fuel cell transfer line)
    example: The manufacturer article says C-22 bellows were tested for this repair and that their fatigue life far exceeded that of 304L stainless steel, and it cites the fatigue test report MTB-688-87 (2 December 1987).
    source: haynes-shuttle-bellows
    where: Article text, paragraph on fuel cell servicing system bellows
  - application: structures
    device: 'Process equipment in the chemical and environmental industries: reactors, heat exchangers, columns, agitators, pipelines and spray systems'
    example: The datasheet lists chemical process plants, exhaust gas cleaning systems and wastewater treatment as typical applications, and says seawater and chloride-containing media are suitable for the material.
    source: zapp-c22
    where: Typical application list (environmental technology and chemical engineering)
supply:
  - subject: Nickel (mine production)
    producers:
      - country: Indonesia
        share_percent: 66.7
        year: 2025
      - country: Philippines
        share_percent: 6.9
        year: 2025
      - country: Russia
        share_percent: 5.1
        year: 2025
    critical_lists: []
    recycling: 'USGS: nickel recovered from scrap accounted for approximately 60 % of apparent U.S. consumption in 2025; most secondary nickel is in stainless-steel scrap.'
    substitutes:
      - 'USGS: titanium alloys can substitute for nickel or nickel-base alloys in corrosive environments; low-nickel, duplex or ultrahigh-chromium stainless steels replace austenitic grades in construction.'
    source: usgs-mcs2026-nickel
    where: World Mine Production and Reserves table, row Indonesia 2,600,000 t, Philippines 270,000 t and Russia 200,000 t of world total 3,900,000 t (2025e); shares calculated by Space Mushroom from those printed values. Recycling and Substitutes sections.
  - subject: Chromium (mine production, chromium content)
    producers:
      - country: South Africa
        share_percent: 45.1
        year: 2025
      - country: Turkey
        share_percent: 17.6
        year: 2025
      - country: Kazakhstan
        share_percent: 13.7
        year: 2025
    critical_lists: []
    recycling: Not recorded in this run.
    substitutes: []
    source: usgs-mcs2026-chromium
    where: World Mine Production and Reserves table, rows South Africa 23,000, Turkey 9,000 and Kazakhstan 7,000 of world total 51,000 thousand t chromium content (2025e); shares calculated by Space Mushroom from those printed values.
  - subject: Tungsten (mine production, tungsten content)
    producers:
      - country: China
        share_percent: 78.8
        year: 2025
      - country: Vietnam
        share_percent: 3.5
        year: 2025
      - country: Russia
        share_percent: 2.4
        year: 2025
    critical_lists: []
    recycling: Not recorded in this run.
    substitutes: []
    source: usgs-mcs2026-tungsten
    where: World Mine Production and Reserves table, rows China 67,000, Vietnam 3,000 and Russia 2,000 of world total 85,000 t tungsten content (2025); shares calculated by Space Mushroom from those printed values.
documents:
  - title: Zapp Materials Engineering, HASTELLOY C-22 alloy data sheet (last revision October 2020)
    type: datasheet
    url: https://www.zapp.com/fileadmin/user_upload/HASTELLOY_C-22-alloy-Datasheet.pdf
    year: 2020
  - title: Haynes International, HASTELLOY C-22 alloy product page
    type: datasheet
    url: https://www.haynesintl.com/en/alloy/hastelloy-c-22/
  - title: High Temp Metals, Hastelloy C-22 technical data (average properties, manufacturer-derived)
    type: datasheet
    url: https://www.hightempmetals.com/techdata/hitempHastC22data.php
  - title: Haynes International, Hastelloy C-22 alloy for cryogenic bellows in the Space Shuttle (summary of NASA reports MTB-325-87A and MTB-688-87)
    type: report
    url: https://haynesintl.com/en/hastelloy-c-22-alloy-for-cryogenic-bellows-in-the-space-shuttle/
  - title: Summers et al., Phase Stability and Mechanical Properties of C-22 Alloy Aged in the Temperature Range 590 to 760 C for 16,000 Hours, MRS Online Proceedings Library 556, 1999
    type: paper
    url: https://doi.org/10.1557/PROC-556-919
    year: 1999
  - title: Stanford Advanced Materials, Hastelloy safety data sheet (covers C276 and C22)
    type: sds
    url: https://powder.samaterials.com/tds/1689650668-Hastelloy-Safety-Data-Sheet.pdf
  - title: 'USGS Mineral Commodity Summaries 2026: Nickel'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf
    year: 2026
  - title: 'USGS Mineral Commodity Summaries 2026: Chromium'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-chromium.pdf
    year: 2026
  - title: 'USGS Mineral Commodity Summaries 2026: Tungsten'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-tungsten.pdf
    year: 2026
gaps:
  - 'AISI or SAE code not found: the Matthey datasheet that lists B650 returned HTTP 404 in this run, and the other fetched pages do not print an AISI code. No AISI designation is recorded.'
  - The Zapp datasheet prints thermal conductivity as 9,6 W/(m·K) at room temperature, which differs from the 10.1 W/(m·K) at 48 °C recorded from the manufacturer-derived table. Only the 10.1 value is entered because the Zapp value uses a comma decimal and was not checked against a second page.
  - Charpy impact at room temperature (419 ft-lbf, 568 J, mill-annealed plate) and hardness (Rb 88 to 95) are printed on the manufacturer page but not entered; the Charpy value at -196 °C is entered under the non-canonical name charpy_impact_energy.
  - Critical mineral list status for nickel, chromium and tungsten was not printed in the fetched USGS 2026 summaries, so critical_lists is empty for all three.
  - Recycling and substitutes for chromium and tungsten were not recorded in this run.
  - Composition in the Stanford safety data sheet (nickel 50 to 60 %, chromium 14.5 to 22.5 %) and its melting point (about 1325 to 1370 °C) differ from the manufacturer values and were not used.
  - No hydrogen, oxygen or propellant compatibility data were found for C-22 in this run, so the cryogenic-fuel uses rest on bellows test and service reports only.
  - No atomic oxygen, outgassing (total mass loss) or radiation data were found for C-22.
  - No open-access corrosion rate paper for C-22 in ferric chloride or chloride pitting was opened. The corrosion values come from the manufacturer test data only.
  - The Summers et al. 1999 abstract gives aging temperatures and durations and qualitative results only; no tensile, impact or corrosion numbers are recorded from it.
  - The Haynes product page was read through a summarizing fetch, not as raw text; values from it are checked by verify-values against the page as published.
  - The reseller page that carries the average properties is not the manufacturer's own datasheet; its values match the manufacturer data on the Haynes page, but the Haynes H-2019 PDF itself was not opened.
  - Hot forming and solution annealing temperatures are given as ranges in the datasheet (Zapp), not as single values.
  - The element roles in the recipe are general metallurgy, not statements from the fetched pages, except where a page says so.
  - Melting point range is from the reseller table; the datasheet melting range (1.357 to 1.399 °C with decimal commas) was not used because of the printed format.
sources:
  zapp-c22:
    title: HASTELLOY C-22 alloy Data Sheet, Zapp Materials Engineering GmbH (last revision October 2020)
    id: DIN 17744, material number 2.4602, NiCr21Mo14W, UNS N06022
    url: https://www.zapp.com/fileadmin/user_upload/HASTELLOY_C-22-alloy-Datasheet.pdf
    year: 2020
    kind: datasheet
    license: Manufacturer data sheet, general information only (cited, not reproduced)
  haynes-c22:
    title: HASTELLOY C-22 alloy product page, Haynes International
    url: https://www.haynesintl.com/en/alloy/hastelloy-c-22/
    kind: datasheet
    license: Manufacturer web page (cited, not reproduced)
  hightemp-c22:
    title: Hastelloy C-22 technical data, High Temp Metals (average physical, tensile and expansion data)
    url: https://www.hightempmetals.com/techdata/hitempHastC22data.php
    kind: datasheet
    license: Reseller web page (cited, not reproduced)
  haynes-shuttle-bellows:
    title: Hastelloy C-22 alloy for cryogenic bellows in the Space Shuttle, Haynes International (summary of NASA reports MTB-325-87A and MTB-688-87)
    url: https://haynesintl.com/en/hastelloy-c-22-alloy-for-cryogenic-bellows-in-the-space-shuttle/
    kind: web
    license: Manufacturer web page (cited, not reproduced)
  summers-1999-c22:
    title: Phase Stability and Mechanical Properties of C-22 Alloy Aged in the Temperature Range 590 to 760 C for 16,000 Hours (Summers, Wall, Kumar, Matthews, Rebak), MRS Online Proceedings Library 556, paper 919
    id: DOI 10.1557/PROC-556-919
    url: https://doi.org/10.1557/PROC-556-919
    year: 1999
    kind: paper
    license: Abstract read via DOI page (cited, not reproduced)
  stanford-sds-hastelloy:
    title: Hastelloy safety data sheet, Stanford Advanced Materials (covers Hastelloy C276 and C22)
    url: https://powder.samaterials.com/tds/1689650668-Hastelloy-Safety-Data-Sheet.pdf
    kind: datasheet
    license: Supplier safety data sheet (cited, not reproduced)
  usgs-mcs2026-nickel:
    title: Mineral Commodity Summaries 2026, Nickel, U.S. Geological Survey
    id: USGS MCS 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  usgs-mcs2026-chromium:
    title: Mineral Commodity Summaries 2026, Chromium, U.S. Geological Survey
    id: USGS MCS 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-chromium.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  usgs-mcs2026-tungsten:
    title: Mineral Commodity Summaries 2026, Tungsten, U.S. Geological Survey
    id: USGS MCS 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-tungsten.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
license: CC-BY-4.0
updated: '2026-10-26'
review:
  status: draft
  method: assistant
  checked_values: 19
  unreachable: 2
  caveats: 5
  note: 'Values were read by an AI assistant on 2026-10-26 from the pages and PDFs named in each entry. Unreachable: Matthey datasheet (HTTP 404) and PubChem nickel record (browser check page). Caveats: the Haynes product page was read through a summarizing fetch; the average properties come from a reseller page; supply shares are calculated from printed tonnages; the corrosion values are laboratory data; no spacecraft data beyond launch-site and servicing bellows were found.'
story:
  risk_groups:
    - title: For people
      lead: The solid alloy is not classified as hazardous, but grinding, melting or welding can make dust and fume that matter.
      level: 1
      verdict: Low hazard as solid
      points:
        - label: Solid metal
          line: The Stanford safety data sheet for Hastelloy C276 and C22 says the solid is not classified as hazardous under 29 CFR 1910.1200.
        - label: Dust and fume
          line: Grinding, melting or welding can produce dust or fume that is hazardous if inhaled. The sheet gives nickel 1 mg/m3 (OSHA) and chromium 0.5 mg/m3 (ACGIH) as exposure limits.
    - title: If it fails
      lead: These are failure routes found in the sources. The space-related evidence is a launch-site bellows test, not a failure record.
      points:
        - label: Long heat exposure
          line: A 16000 h aging study at 593 to 760 °C found mu phase on grain boundaries, with strength up and ductility down.
        - label: Cold work
          line: The datasheet says a new solution anneal is needed after cold forming above 15 %, because cold work changes the material.
        - label: Hot acid
          line: 'Hot hydrochloric acid is aggressive: the laboratory rate for 10 % HCl is 11.68 mm/y at boiling.'
    - title: Handling and storage
      points:
        - label: Heat treatment
          line: Solution anneal near 1121 °C, then water quench, or air cooling for sections under 10 mm.
        - label: Welding
          line: TIG or MIG welding with low heat input keeps corrosion resistance; preheat and post-weld heat treatment are usually not needed.
  why: Hastelloy C-22 is a nickel alloy with about 20 to 22.5 % chromium, 12.5 to 14.5 % molybdenum and 2.5 to 3.5 % tungsten. That mix makes it resist pitting and crevice attack in hot chloride solutions, in oxidizing and reducing acids, and in seawater. The manufacturer test data show zero crevice attack in 180 days of seawater exposure and a critical crevice temperature of 80 °C in ferric chloride. At the Space Shuttle launch site, C-22 bellows replaced 304L stainless steel, which had failed by pitting.
  uses:
    - where: Launch-site cryogenic lines
      line: Vacuum-jacketed cryogenic supply lines at the Shuttle launch site were first 304L stainless steel, which pitted. Hastelloy C-22 bellows were welded on site after a test that found it the best of all alloys tested.
    - where: Fuel cell servicing bellows
      line: Bellows for the LC-39B fuel cell servicing system repair were made of C-22, and their fatigue life far exceeded that of 304L, according to the manufacturer article.
    - where: Chemical and environmental plants
      line: The datasheet lists reactors, heat exchangers, columns, agitators, pipelines, exhaust gas cleaning and wastewater treatment as typical uses.
  can_do:
    - label: Resist chloride pitting
      value: critical crevice temperature 80 °C
      line: In the ASTM G 48 test in acidified 6 % ferric chloride, C-22 shows no pitting up to above 150 °C and a crevice temperature of 80 °C.
    - label: Carry heat
      value: 10.1 W/(m·K)
      benchmark: thermal_conductivity
      line: Thermal conductivity is 10.1 W/(m·K) at 48 °C and 21.3 W/(m·K) at 600 °C, so it conducts heat poorly for a metal.
    - label: Weight
      value: 8.69 g/cm3
      benchmark: density
      line: Density is 8.69 g/cm3 at 24 °C in the average properties table.
    - label: Melting
      value: 1357 to 1399 °C
      benchmark: melting_point
      line: The melting range is 1357 to 1399 °C (2475 to 2550 °F).
    - label: Strength
      value: 310 MPa minimum yield
      benchmark: yield_strength
      line: The minimum Rp0.2 yield strength at room temperature is 310 MPa for solution-annealed sheet up to 50 mm, and the average for thinner sheet is 403 MPa.
    - label: Stretch
      value: 57 %
      benchmark: elongation
      line: Average elongation at room temperature for solution-treated sheet is 57 %, and the minimum in the datasheet is 45 %.
  compare: The Haynes critical crevice temperature test in acidified 6 % ferric chloride gives C-22 a value of 80 °C, against 55 °C for C-276, 40 °C for alloy 625 and 0 °C for 316L, all printed on the same page. The page also says C-22 has much higher resistance to oxidizing media than C-276. Its density of 8.69 g/cm3 and its thermal conductivity of 10.1 W/(m·K) at 48 °C are the figures to weigh against lighter or better-conducting metals.
  compare_rows:
    - label: Density
      benchmark: density
    - label: Thermal conductivity
      benchmark: thermal_conductivity
    - label: Thermal expansion
      benchmark: cte
  handling:
    - Re-anneal after cold forming above 15 %, as the datasheet requires.
    - Keep hot forming between about 1232 °C and 954 °C, because the working range is narrow.
    - Use low heat input when welding, and do not preheat or post-weld heat treat unless the specification requires it.
  good_for:
    - 'Chloride and seawater service: no crevice attack in 180 days of seawater exposure (manufacturer test data).'
    - Chemical plants with oxidizing and reducing acids, including chlorine and hydrogen chloride processes.
    - Cryogenic lines and bellows in launch-site service, where 304L failed by pitting.
  watch_out:
    - Mu phase forms on grain boundaries after long exposure at 593 to 760 °C, and ductility falls.
    - 'Boiling hydrochloric acid is severe: 11.68 mm/y at boiling for 10 % HCl in the laboratory data.'
    - Thermal conductivity is low at 10.1 W/(m·K), and density is 8.69 g/cm3.
    - No atomic oxygen, outgassing or radiation data were found for this alloy.
  verdict: Hastelloy C-22 is a corrosion-resistant nickel alloy for hot chloride, oxidizing and mixed acid service, with zero crevice attack in 180 days of seawater and a 80 °C critical crevice temperature in ferric chloride. It is heavy and conducts heat poorly, it can form brittle mu phase after long exposure at 593 to 760 °C, and it is severely attacked by boiling hydrochloric acid. Its spacecraft record is limited to Shuttle launch-site and servicing bellows; no outgassing or atomic oxygen data were found.
  recipe:
    line: C-22 is a solid-solution nickel alloy (Ni balance) with chromium, molybdenum, tungsten and iron, and small amounts of carbon, cobalt, silicon, manganese, vanadium, phosphorus and sulphur. Semi-finished products are solution annealed at 1105 to 1135 °C and cooled in water, compressed air or inert gas (Zapp datasheet). The alloy is supplied as sheet, strip, tube, bar, forged parts, wire and welding consumables.
    parts:
      - name: Nickel
        symbol: Ni
        share: balance (remainder)
        role: Matrix of the alloy; gives the austenitic structure and most of the corrosion resistance in reducing and oxidizing media.
      - name: Chromium
        symbol: Cr
        share: 20.0 to 22.5 wt%
        role: Forms the passive oxide film that resists oxidizing acids and chloride attack.
      - name: Molybdenum
        symbol: Mo
        share: 12.5 to 14.5 wt%
        role: Improves resistance to pitting and crevice attack in chloride solutions.
      - name: Iron
        symbol: Fe
        share: 2.0 to 6.0 wt%
        role: Present as a specified addition; the sources read in this run do not state its function.
      - name: Tungsten
        symbol: W
        share: 2.5 to 3.5 wt%
        role: Specified addition; the sources read in this run do not state its function, but the manufacturer says C-22 has much better thermal stability than C-276.