Incoloy 800 UNS N08800

spore: profile
id: incoloy-800
spore_version: 0.2
family: nickel-alloys
name: Incoloy 800
abbreviation: UNS N08800
role: high-temperature corrosion-resistant alloy
category: metals
type: nickel-superalloys
summary: |
  Incoloy 800 (UNS N08800, Werkstoff 1.4876) is an austenitic iron-nickel-chromium alloy with 30.0 to 35.0 % nickel and 19.0 to 23.0 % chromium. Its density is 7.94 g/cm3 and it melts between 1357 and 1385 °C. Annealed, it has a yield strength of 250 MPa at 25 °C and 176 MPa at 650 °C. The bulletin says it is used for strength and corrosion resistance up to about 816 °C (1500 °F). The 800H and 800HT grades (UNS N08810 and N08811) are carbon-richer versions for higher creep strength. This profile gives values for alloy 800 only.
best_for: Strength and oxidation resistance up to about 816 °C (1500 °F), with resistance to chloride stress-corrosion cracking
weakest_at: Creep and rupture strength above about 816 °C, where the bulletin points to alloys 800H and 800HT, and sensitisation after heating at 540 to 760 °C
identity:
  formula: 'Iron-nickel-chromium austenitic alloy: Ni 30.0 to 35.0 %, Cr 19.0 to 23.0 %, Fe 39.5 % minimum, C 0.10 % maximum, Al 0.15 to 0.60 %, Ti 0.15 to 0.60 %, Mn 1.50 % maximum, Si 1.0 % maximum, Cu 0.75 % maximum, S 0.015 % maximum'
  source: special-metals-800
  where: Table 2, Limiting Chemical Composition, alloy 800 (Table 1 of the 800H and 800HT bulletin gives the same nickel, chromium and iron limits)
  designations:
    - system: UNS
      code: N08800
      source: special-metals-800
      where: Available Products and Specifications section, 'INCOLOY alloy 800 is designated as UNS N08800'
    - system: EN
      code: '1.4876'
      source: special-metals-800
      where: Available Products and Specifications section, 'Werkstoff Number 1.4876'
    - system: UNS
      code: N08810
      note: 800H, a separate UNS number in the same family; values in this profile are for alloy 800
      source: special-metals-800h
      where: Table 1, UNS designation column N08810 (alloy 800H)
    - system: UNS
      code: N08811
      note: 800HT, a separate UNS number in the same family; values in this profile are for alloy 800
      source: special-metals-800h
      where: Table 1, UNS designation column N08811 (alloy 800HT)
    - system: ASTM
      code: A240
      note: plate, sheet and strip, with A480
      source: aircraftmaterials
      where: Specifications list, ASTM A 240/A 480
    - system: ASTM
      code: B163
      note: seamless condenser and heat exchanger tubes
      source: aircraftmaterials
      where: Specifications list, ASTM B 163
    - system: ASTM
      code: B408
      note: rod and bar
      source: special-metals-800
      where: Rod, Bar, Wire, Forgings and Forging Stock, ASTM B 408
    - system: ASTM
      code: B409
      note: plate, sheet and strip
      source: special-metals-800
      where: Plate, Sheet, and Strip, ASTM B 409/B 906
    - system: AMS
      code: '5766'
      note: rod and bar
      source: special-metals-800
      where: Rod, Bar, Wire, Forgings and Forging Stock, SAE/AMS 5766
    - system: AMS
      code: '5871'
      note: plate, sheet and strip
      source: special-metals-800
      where: Plate, Sheet, and Strip, SAE/AMS 5871
    - system: Trade name
      code: INCOLOY alloy 800
      source: special-metals-800
      where: Title block and Table 2 heading
    - system: AFNOR
      code: Z10NC32.21
      source: tachart
      where: Alias list on the INCOLOY 800 page
tags:
  environments: []
  stresses:
    - extreme-heat
  applications:
    - thermal-control
    - structures
properties:
  - benchmark: density
    label: Density, alloy 800
    value: 7.94
    unit: g/cm3
    scope: material
    conditions:
      grade: alloy 800 (UNS N08800)
      unit_in_source: 0.287 lb/in3
    method: Value printed in a manufacturer technical bulletin, physical constants table
    status: ground
    source: special-metals-800
    where: Table 3, Physical Constants, row Density, g/cm3
  - benchmark: melting_point
    label: Melting range, alloy 800
    value: 1357
    value_high: 1385
    bound: range
    unit: °C
    scope: material
    conditions:
      grade: alloy 800 (UNS N08800)
      unit_in_source: 2475-2525 °F
    method: Melting range printed in a manufacturer technical bulletin
    status: ground
    source: special-metals-800
    where: Table 3, Physical Constants, row Melting Range, °C
  - benchmark: specific_heat
    label: Specific heat, 0 to 100 °C
    value: 460
    unit: J/kg·°C
    scope: material
    conditions:
      grade: alloy 800 (UNS N08800)
      temperature: 0 to 100 °C
      unit_in_source: 0.11 Btu/lb·°F over 32 to 212 °F
    method: Value printed in a manufacturer technical bulletin
    status: ground
    source: special-metals-800
    where: Table 3, Physical Constants, row Specific Heat (0-100°C)
  - benchmark: elastic_modulus
    label: Modulus of elasticity at 20 °C, annealed
    value: 196.5
    unit: GPa
    scope: material
    conditions:
      grade: alloy 800 (UNS N08800)
      temperature: 20 °C
      temper: annealed
      method_in_source: dynamic method
      unit_in_source: 28.50 x 10^3 ksi at 75 °F
    method: Value printed in a manufacturer technical bulletin, footnote states the dynamic method
    status: ground
    source: special-metals-800
    where: Table 4, Modulus of Elasticity, row 20 °C, column Modulus 103 ksi/GPa
  - benchmark: poissons_ratio
    label: Poisson's ratio at 20 °C, annealed
    value: 0.339
    unit: '-'
    scope: material
    conditions:
      grade: alloy 800 (UNS N08800)
      temperature: 20 °C
      temper: annealed
      method_in_source: calculated from moduli of elasticity
    method: Value printed in a manufacturer technical bulletin
    status: ground
    source: special-metals-800
    where: Table 4, Modulus of Elasticity, row 20 °C, column Poisson's Ratio
  - benchmark: thermal_conductivity
    label: Thermal conductivity at 20 °C, annealed
    value: 11.5
    unit: W/m°C
    scope: material
    conditions:
      grade: alloy 800 (UNS N08800)
      temperature: 20 °C
      temper: annealed
      unit_in_source: 80 Btu·in/ft2·h·°F
    method: Value printed in a manufacturer technical bulletin, table headed as annealed material
    status: ground
    source: special-metals-800
    where: Table 5, Electrical and Thermal Properties, row 20 °C (W/m°C), column Thermal Conductivity
  - benchmark: electrical_resistivity
    label: Electrical resistivity at 20 °C, annealed
    value: 0.989
    unit: µΩ·m
    scope: material
    conditions:
      grade: alloy 800 (UNS N08800)
      temperature: 20 °C
      temper: annealed
      unit_in_source: 595 ohm·circ mil/ft at 70 °F
    method: Value printed in a manufacturer technical bulletin, table headed as annealed material
    status: ground
    source: special-metals-800
    where: Table 5, Electrical and Thermal Properties, row 20 °C (µΩ·m), column Electrical Resistivity
  - benchmark: cte
    label: Coefficient of thermal expansion, 21 to 100 °C, annealed
    value: 14.4
    unit: µm/m/°C
    scope: material
    conditions:
      grade: alloy 800 (UNS N08800)
      temperature: between 21 °C and 100 °C
      temper: annealed
      basis: mean value between 70 °F and the temperature shown
    method: Value printed in a manufacturer technical bulletin
    status: ground
    source: special-metals-800
    where: Table 5, Electrical and Thermal Properties, row 100 °C, column Coefficient of Expansion (µm/m/°C)
  - benchmark: curie_temperature
    label: Curie temperature, alloy 800
    value: -115
    unit: °C
    scope: material
    conditions:
      grade: alloy 800 (UNS N08800)
      unit_in_source: '-175 °F'
    method: Value printed in a manufacturer technical bulletin
    status: ground
    source: special-metals-800
    where: Table 3, Physical Constants, row Curie Temperature, °C
  - benchmark: yield_strength
    label: Yield strength 0.2 % offset at 25 °C, annealed
    value: 250
    unit: MPa
    scope: material
    conditions:
      grade: alloy 800 (UNS N08800)
      temperature: 25 °C (80 °F)
      temper: annealed
      heat_treatment_in_source: annealed at 1800 °F (980 °C), per table footnote a
      unit_in_source: 36.2 ksi
    method: Value printed in a manufacturer technical bulletin, high-temperature hardness and tensile table
    status: ground
    source: special-metals-800
    where: Table 8, Hardness and Tensile Properties at High Temperatures, row Annealed, 80 °F (25 °C), column Yield Strength (0.2 % Offset) MPa
  - benchmark: ultimate_tensile_strength
    label: Tensile strength at 25 °C, annealed
    value: 590
    unit: MPa
    scope: material
    conditions:
      grade: alloy 800 (UNS N08800)
      temperature: 25 °C (80 °F)
      temper: annealed
      heat_treatment_in_source: annealed at 1800 °F (980 °C), per table footnote a
      unit_in_source: 85.5 ksi
    method: Value printed in a manufacturer technical bulletin, high-temperature hardness and tensile table
    status: ground
    source: special-metals-800
    where: Table 8, Hardness and Tensile Properties at High Temperatures, row Annealed, 80 °F (25 °C), column Tensile Strength MPa
  - benchmark: yield_strength
    label: Yield strength 0.2 % offset at 650 °C, annealed
    value: 176
    unit: MPa
    scope: material
    conditions:
      grade: alloy 800 (UNS N08800)
      temperature: 650 °C (1200 °F)
      temper: annealed
      heat_treatment_in_source: annealed at 1800 °F (980 °C), per table footnote a
      unit_in_source: 25.5 ksi
    method: Value printed in a manufacturer technical bulletin, high-temperature tensile table
    status: ground
    source: special-metals-800
    where: Table 8, Hardness and Tensile Properties at High Temperatures, row Annealed, 1200 °F (650 °C), column Yield Strength (0.2 % Offset) MPa
  - benchmark: ultimate_tensile_strength
    label: Tensile strength at 650 °C, annealed
    value: 405
    unit: MPa
    scope: material
    conditions:
      grade: alloy 800 (UNS N08800)
      temperature: 650 °C (1200 °F)
      temper: annealed
      heat_treatment_in_source: annealed at 1800 °F (980 °C), per table footnote a
      unit_in_source: 58.7 ksi
    method: Value printed in a manufacturer technical bulletin, high-temperature tensile table
    status: ground
    source: special-metals-800
    where: Table 8, Hardness and Tensile Properties at High Temperatures, row Annealed, 1200 °F (650 °C), column Tensile Strength MPa
  - benchmark: yield_strength
    label: Yield strength 0.2 % offset at 30 °C, cold-drawn rod
    value: 690
    unit: MPa
    scope: material
    conditions:
      grade: alloy 800 (UNS N08800)
      temperature: 30 °C (85 °F)
      temper: cold-drawn rod, as drawn, 1 in (25 mm) diameter
      unit_in_source: 100.0 ksi
    method: Value printed in a manufacturer technical bulletin, cold-drawn rod table
    status: ground
    source: special-metals-800
    where: Table 7, Tensile Properties of Cold-Drawn Rod, row 85 °F (30 °C), column Yield Strength (0.2 % Offset) MPa
  - benchmark: ultimate_tensile_strength
    label: Tensile strength at 30 °C, cold-drawn rod
    value: 771
    unit: MPa
    scope: material
    conditions:
      grade: alloy 800 (UNS N08800)
      temperature: 30 °C (85 °F)
      temper: cold-drawn rod, as drawn, 1 in (25 mm) diameter
      unit_in_source: 111.8 ksi
    method: Value printed in a manufacturer technical bulletin, cold-drawn rod table
    status: ground
    source: special-metals-800
    where: Table 7, Tensile Properties of Cold-Drawn Rod, row 85 °F (30 °C), column Tensile Strength MPa
  - benchmark: elongation
    label: Elongation at 30 °C, cold-drawn rod
    value: 17
    unit: '%'
    scope: material
    conditions:
      grade: alloy 800 (UNS N08800)
      temperature: 30 °C (85 °F)
      temper: cold-drawn rod, as drawn, 1 in (25 mm) diameter
    method: Value printed in a manufacturer technical bulletin
    status: ground
    source: special-metals-800
    where: Table 7, Tensile Properties of Cold-Drawn Rod, row 85 °F (30 °C), column Elongation %
  - benchmark: fatigue_strength
    label: Rotating-beam fatigue strength at 10^8 cycles, room temperature, hot-rolled annealed rod
    value: 214
    unit: MPa
    scope: material
    conditions:
      grade: alloy 800 (UNS N08800)
      temperature: room temperature
      temper: hot-rolled, annealed 1950 °F (1065 °C) for 10 min, air cooled
      test: rotating beam on polished specimens
      cycles: 10^8
      unit_in_source: 31 ksi
    method: Value printed in a manufacturer technical bulletin, room-temperature fatigue table
    status: ground
    source: special-metals-800
    where: Table 12, Room-Temperature Fatigue Strength of Rod, row Hot-Rolled Annealed, 108 cycles, column MPa
  - benchmark: charpy_impact_energy
    label: Charpy keyhole impact energy at 21 °C, annealed plate, longitudinal
    value: 122
    unit: J
    scope: material
    conditions:
      grade: alloy 800 (UNS N08800)
      temperature: 21 °C (70 °F)
      temper: annealed plate, 0.8 in (20 mm) thick, annealed 1800 °F (980 °C)
      specimen: longitudinal
      unit_in_source: 89.8 ft·lbf
      basis: average of three tests
    method: Value printed in a manufacturer technical bulletin
    status: ground
    source: special-metals-800
    where: Table 9, Impact Strength of Alloy 800, annealed plate, row 70 °F (21 °C) Longitudinal, column J
corrosion:
  - environment: Boiling 65 % nitric acid (Huey test), after heating at 540 to 760 °C
    headline: Sensitised alloy 800 corrodes intergranularly; the Huey test separates sensitised from unsensitised material.
    effect: The bulletin says an average rate substantially over about 24 mils per year (0.61 mm/yr) over five 48-hour periods indicates that the specimen is sensitised to some degree. Figures 12 and 13 show Huey rates after different sensitising treatments.
    rating: moderate
    conditions:
      test: Huey test, five consecutive 48-hour periods in boiling 65 % nitric acid
      sensitising_range: 1000 to 1400 °F (540 to 760 °C)
    source: special-metals-800
    where: Corrosion Resistance section, Huey test paragraph
  - environment: Chloride solutions under tensile stress
    headline: Alloy 800 is relatively free from chloride stress-corrosion cracking, though it can be made to crack in severe laboratory tests.
    effect: The bulletin attributes the resistance to its nickel content, and says alloy 800 is commonly used to replace materials that have failed in service from stress-corrosion cracking. No crack-growth rate is given.
    rating: low
    conditions:
      basis: qualitative statement in the bulletin; no test numbers given for chloride cracking
    source: special-metals-800
    where: Microstructure and Metallurgy section, chloride stress-corrosion paragraph
  - environment: High-temperature oxidising, carburising and sulphidising gases
    headline: Chromium and nickel give alloy 800 resistance to oxidation, carburisation and sulphidation at elevated temperature.
    effect: The bulletin says that at elevated temperatures alloy 800 offers resistance to oxidation, carburisation and sulphidation, with rupture and creep strength. It adds that iron gives resistance to internal oxidation.
    rating: low
    conditions:
      basis: qualitative statement in the bulletin introduction; no rates given
    source: special-metals-800
    where: Introduction page, paragraph beginning 'INCOLOY alloy 800 (UNS N08800/W. Nr. 1.4876) is a widely used material'
risks:
  hazards:
    - text: 'Special Metals safety data sheet for the Incoloy family (revised 30 November 2016): as shipped, these complex alloys in massive form have no known toxicological properties other than allergic reactions in people sensitive to the metals in them. Hazardous fume or dust emissions may be released during remelting, grinding, cutting or welding, and the classifications listed relate to those fumes and dust: skin sensitisation (H317), respiratory sensitisation (H334), respiratory irritation (H335), carcinogenicity category 1B (H350), suspected of damaging the unborn child (H361d), and organ damage from prolonged exposure (H372, H373).'
      ghs:
        - H317
        - H334
        - H335
        - H350
        - H361d
        - H372
        - H373
      source: special-metals-sds
      where: Section 2.1, Classification of the substance or mixture, CLP paragraph
    - text: NIST Standard Reference Material 1246 (Incoloy 800, wrought disk) is not classified under OSHA 29 CFR 1910.1200 as a physical or health hazard, and has no pictograms, hazard statements or signal word. It is exempt as an article.
      ghs: []
      source: nist-srm1246
      where: Product Identifier and OSHA paragraph, page 1
  failure_risks:
    - mode: Intergranular attack after sensitisation
      trigger: Exposure to 540 to 760 °C (1000 to 1400 °F), for example from welding heat, followed by an aggressive medium such as nitric acid
      consequence: Alloy 800 can become susceptible to intergranular corrosion. In the Huey test, boiling 65 % nitric acid over five 48-hour periods, an average rate substantially over about 24 mils per year (0.61 mm/yr) indicates sensitisation.
      severity: moderate
      source: special-metals-800
      where: Corrosion Resistance section, Huey test paragraph
    - mode: Creep and rupture at high temperature
      trigger: Long-term loading at high temperature; the bulletin's creep and rupture curves cover 500 to 705 °C
      consequence: The bulletin says alloy 800 is not normally used where optimum creep-rupture strength is needed; alloys 800H and 800HT are used instead. The bulletin's creep and rupture curves (Figures 7 and 8) are typical data and are not recorded as values here.
      severity: moderate
      source: special-metals-800
      where: Creep and Rupture Properties section, paragraph after Figure 7
    - mode: Stress-corrosion cracking in chloride
      trigger: Chloride solutions under tensile stress
      consequence: The bulletin says alloy 800 is relatively free from chloride stress-corrosion cracking, though it can be made to crack in severe laboratory tests.
      severity: low
      source: special-metals-800
      where: Microstructure and Metallurgy section, chloride paragraph
  handling:
    - text: Clean the metal of oil, paint, grease and shop soil before heating, and heat in a low-sulfur, reducing atmosphere to avoid excessive oxidation.
      source: special-metals-800
      where: Working Instructions, Heating and Pickling
    - text: 'Anneal at about 1800 °F (980 °C): annealing is reasonably complete after 10 to 15 minutes at 1800 °F. Grain growth can occur above 1800 °F (980 °C).'
      source: special-metals-800
      where: Working Instructions, annealing paragraph
    - text: Do not breathe dust or fumes when cutting, grinding or welding, and wear appropriate protective equipment when dusts or fumes are created.
      source: special-metals-sds
      where: Section 7.1, Precautions for safe handling
  mitigations: []
uses:
  - application: thermal-control
    device: Heat exchangers, piping and steam-generator tubing
    example: Used for heat exchangers and piping in nitric acid media, for steam-generator tubing in nuclear power plants, for digester-liquor heaters in paper pulp production, and for air-cooling heat exchangers in petroleum processing.
    source: special-metals-800
    where: Introduction, paragraph beginning 'INCOLOY alloy 800 is used in a variety of applications'
  - application: structures
    device: Heat-treating baskets, trays and fixtures
    example: Used for heat-treating equipment such as baskets, trays and fixtures. The bulletin says equipment design at service temperatures up to about 1500 °F (816 °C) is usually based on tensile properties.
    source: special-metals-800
    where: Introduction, applications paragraph; Mechanical Properties section
supply:
  - subject: Nickel (30.0 to 35.0 % of alloy 800)
    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
      - country: Canada
        share_percent: 3.6
        year: 2025
      - country: New Caledonia
        share_percent: 3.6
        year: 2025
    critical_lists: []
    recycling: 'USGS: nickel recovered from scrap accounted for approximately 60 % of apparent consumption in 2025, and most recycled nickel was used to produce new alloys and stainless steel.'
    substitutes:
      - 'USGS: low-nickel, duplex or ultrahigh-chromium stainless steels have been substituted for austenitic grades; titanium alloys can substitute for nickel or nickel-base alloys in corrosive environments.'
    source: usgs-mcs2026-nickel
    where: 'World Mine Production and Reserves table, 2025e column: Indonesia 2,600,000 t, Philippines 270,000 t, Russia 200,000 t, Canada 140,000 t, New Caledonia 140,000 t, world total (rounded) 3,900,000 t. Shares were calculated by Space Mushroom from these printed values; Recycling and Substitutes sections.'
  - subject: Chromium (19.0 to 23.0 % of alloy 800)
    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
      - country: India
        share_percent: 5.9
        year: 2025
    critical_lists: []
    substitutes:
      - 'USGS: chromium has no substitute in stainless steel, the leading end use, or in superalloys, the major strategic end use.'
    source: usgs-mcs2026-chromium
    where: 'World Mine Production and Reserves table, 2025e column: South Africa 23,000, Turkey 9,000, Kazakhstan 7,000, India 3,000, world total (rounded) 51,000 thousand t. The table header gives chromium content, but footnote 12 says mine production is reported in gross weight, so the units are as printed and the shares are calculated by Space Mushroom from the printed totals. Substitutes section.'
documents:
  - title: Special Metals, INCOLOY alloy 800 technical bulletin (UNS N08800, W.Nr. 1.4876)
    type: datasheet
    url: https://www.specialmetals.com/documents/technical-bulletins/incoloy/incoloy-alloy-800.pdf
  - title: Special Metals, INCOLOY alloys 800H and 800HT technical bulletin (UNS N08810, N08811)
    type: datasheet
    url: https://www.specialmetals.com/documents/technical-bulletins/incoloy/incoloy-alloy-800h-800ht.pdf
  - title: Special Metals safety data sheet for Inconel, Incoloy, Monel and related alloys (revision 30 November 2016)
    type: sds
    url: https://www.specialmetals.com/documents/msds.pdf
    year: 2016
  - title: NIST Standard Reference Material 1246, Incoloy 800, safety data sheet (28 April 2014)
    type: sds
    url: https://tsapps.nist.gov/srmext/msds/1246-MSDS.pdf
    year: 2014
  - 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: Aircraft Materials, Incoloy Alloy 800 / 800H / 800HT data page
    type: database
    url: https://aircraftmaterials.com/data/nickel/alloy800.html
  - title: Tachart, INCOLOY 800 alias page
    type: database
    url: https://www.tachart.com/?p=490
  - title: 'Wikipedia: Incoloy'
    type: database
    url: https://en.wikipedia.org/wiki/Incoloy
    year: 2026
gaps:
  - No spacecraft, rocket or satellite use of Incoloy 800 was found in the sources opened. Several NASA searches returned other nickel alloys (Incoloy 903, Inconel 718, Mar-M 247), which are not Incoloy 800, so no space use is recorded.
  - No EN name (X10NiCrAlTi32-20 style) for alloy 800 was taken from a datasheet of this grade. A German datasheet prints that name for 1.4876H and 1.4958 (the 800H grades), so it was not used. The tachart alias list prints 'X10NiCrAITi32.20' with a capital I in the place of a lower-case l, and it was not recorded as an EN name.
  - Values are for alloy 800 only. The 800H and 800HT grades (UNS N08810, N08811) have their own creep and rupture data, and only their composition limits and UNS numbers are recorded here.
  - The Charpy result is recorded under the non-canonical name charpy_impact_energy, because no canonical impact property was found in the property canon.
  - The 800H bulletin gives the same physical constants as the alloy 800 bulletin, but its tensile and creep tables are for 800H and 800HT and were not used.
  - No elongation or reduction of area for annealed alloy 800 at room temperature was found in the bulletin; the elongation value recorded is for cold-drawn rod.
  - No national or ASTM minimum strength values for alloy 800 were opened. The aircraft materials page gives minimums only for 800H and 800HT, which are not used.
  - No nickel or chromium critical-mineral listing was printed in the USGS 2026 summaries opened here, so critical_lists is empty.
  - No PubChem or ECHA record exists for the alloy as a whole. Hazard classifications come from the Special Metals family SDS, which covers the fumes and dust from processing, not the solid metal.
  - Corrosion rates in aqueous media are in a separate Special Metals publication (SMC-026, Resistance to Aqueous Corrosion), which was not opened.
  - Atomic oxygen, outgassing, radiation, and cold-welding results in vacuum were not looked up for this alloy.
sources:
  special-metals-800:
    title: INCOLOY alloy 800 technical bulletin (Special Metals Corporation)
    id: UNS N08800, Werkstoff 1.4876
    url: https://www.specialmetals.com/documents/technical-bulletins/incoloy/incoloy-alloy-800.pdf
    kind: datasheet
    license: Manufacturer technical bulletin (cited, not reproduced)
  special-metals-800h:
    title: INCOLOY alloys 800H and 800HT technical bulletin (Special Metals Corporation)
    id: UNS N08810, UNS N08811
    url: https://www.specialmetals.com/documents/technical-bulletins/incoloy/incoloy-alloy-800h-800ht.pdf
    kind: datasheet
    license: Manufacturer technical bulletin (cited, not reproduced)
  special-metals-sds:
    title: Safety data sheet for Inconel, Incoloy, Monel and related alloys (Special Metals), revision 30 November 2016
    url: https://www.specialmetals.com/documents/msds.pdf
    kind: datasheet
    license: Manufacturer safety data sheet (cited, not reproduced)
  nist-srm1246:
    title: NIST Standard Reference Material 1246, Incoloy 800, safety data sheet
    url: https://tsapps.nist.gov/srmext/msds/1246-MSDS.pdf
    kind: datasheet
    license: NIST public document
  usgs-mcs2026-nickel:
    title: 'Mineral Commodity Summaries 2026: Nickel'
    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'
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-chromium.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  aircraftmaterials:
    title: Incoloy Alloy 800 / 800H / 800HT, Aircraft Materials data page
    url: https://aircraftmaterials.com/data/nickel/alloy800.html
    kind: web
    license: web page (cited, not reproduced)
  tachart:
    title: INCOLOY 800 alias page, Tachart
    url: https://www.tachart.com/?p=490
    kind: web
    license: web page (cited, not reproduced)
  wikipedia-incoloy:
    title: Incoloy, Wikipedia
    url: https://en.wikipedia.org/wiki/Incoloy
    year: 2026
    kind: web
    license: CC BY-SA 4.0 (cited, not reproduced)
license: CC-BY-4.0
updated: '2026-10-26'
review:
  status: draft
  method: assistant
  checked_values: 18
  unreachable: 0
  caveats: 5
  note: 'Values were read by an AI assistant on 2026-10-26 from the Special Metals alloy 800 bulletin (PDF text extracted with pdftotext). Caveats: the bulletin''s strength values are for specific product forms and tempers, listed separately; the 800H and 800HT values are not used; the chromium supply table''s unit wording is inconsistent in the source; the shares are calculated from printed tonnages; no space use was found.'
story:
  risk_groups:
    - title: For people
      lead: The solid alloy is not a known health hazard in the sources. The hazards come from fumes and dust made when it is melted, ground, cut or welded.
      level: 1
      verdict: Hazard from fumes and dust
      points:
        - label: The metal as shipped
          line: The Special Metals safety data sheet says that, as shipped in massive form, these alloys have no known toxicological properties other than allergic reactions in sensitive people. NIST does not classify its Incoloy 800 reference disk as hazardous.
        - label: Fumes and dust
          line: The same sheet classifies the fumes and dust from remelting, grinding, cutting or welding. It lists skin and respiratory sensitisation, carcinogenicity category 1B (H350) and organ damage from repeated exposure (H372, H373).
    - title: If it fails
      lead: These failure routes are in the bulletin. None of them is a measured flight result.
      points:
        - label: Sensitisation
          line: Heating at 540 to 760 °C can make alloy 800 susceptible to intergranular attack in aggressive media. In the Huey test, a rate substantially over about 24 mils per year (0.61 mm/yr) in boiling 65 % nitric acid shows sensitisation.
        - label: Creep
          line: For long-term loading at high temperature, the bulletin points to alloys 800H and 800HT instead of alloy 800.
        - label: Chloride cracking
          line: Alloy 800 is relatively free from chloride stress-corrosion cracking, though it can be made to crack in severe laboratory tests.
    - title: Handling and storage
      points:
        - label: Clean and heat
          line: Clean the surface before heating and heat in a low-sulfur, reducing atmosphere. Annealing at about 1800 °F (980 °C) for 10 to 15 minutes is reasonably complete.
        - label: Ventilate
          line: Ventilate and wear protection when cutting, grinding or welding, and do not breathe the dust or fumes.
  why: Alloy 800 is an iron-nickel-chromium alloy with 30 to 35 % nickel and 19 to 23 % chromium. The nickel keeps the structure austenitic, and the chromium gives resistance to oxidation and to many aqueous media. Annealed, it has a yield strength of 250 MPa at 25 °C and 176 MPa at 650 °C, a density of 7.94 g/cm3 and a melting range of 1357 to 1385 °C. Special Metals invented the 800 series, and Inco created the Incoloy trademark (Wikipedia).
  uses:
    - where: Heat exchangers and piping
      line: The bulletin lists heat exchangers and piping in nitric acid media, steam-generator tubing in nuclear plants, digester-liquor heaters in pulp mills, and air-cooling heat exchangers in petroleum processing.
    - where: Heat-treating fixtures
      line: Baskets, trays and fixtures for heat treatment are a major use, and the bulletin says strength is used up to about 1500 °F (816 °C).
  can_do:
    - label: Strength at room temperature
      value: 250 MPa yield (annealed)
      benchmark: yield_strength
      line: Annealed alloy 800 has a yield strength of 250 MPa and a tensile strength of 590 MPa at 25 °C.
    - label: Strength at 650 °C
      value: 176 MPa yield (annealed)
      benchmark: yield_strength
      line: At 650 °C the annealed alloy has a tensile strength of 405 MPa and a yield strength of 176 MPa.
    - label: Stronger when cold drawn
      value: 690 MPa yield (cold-drawn rod)
      benchmark: yield_strength
      line: Cold-drawn 1 in rod has a yield strength of 690 MPa and a tensile strength of 771 MPa at 30 °C, with 17 % elongation.
    - label: Heat conduction
      value: 11.5 W/m°C at 20 °C
      benchmark: thermal_conductivity
      line: Thermal conductivity of annealed material is 11.5 W/m°C at 20 °C, so the alloy is chosen for strength and corrosion resistance rather than for heat spreading.
    - label: Weight
      value: 7.94 g/cm3
      benchmark: density
      line: Density is 7.94 g/cm3 (0.287 lb/in3).
  compare: Among this site's metals, alloy 800 is a high-temperature corrosion-resistant alloy rather than a conductor or a light structural metal. The strength and density rows are its defining values. The 800H and 800HT grades trade some corrosion behaviour for higher creep strength, so compare them only after checking the grade.
  compare_rows:
    - label: Density
      benchmark: density
    - label: Yield strength at 25 °C
      annealed: null
      benchmark: yield_strength
    - label: Thermal conductivity at 20 °C
      benchmark: thermal_conductivity
  handling:
    - Specify the condition, because strength depends strongly on cold work and heat treatment.
    - Anneal at about 1800 °F (980 °C) for 10 to 15 minutes after forming, and clean the surface before heating.
    - Ventilate when cutting, grinding or welding, and do not breathe fumes or dust.
  good_for:
    - Parts that must keep strength up to about 816 °C (1500 °F), such as heat-treating fixtures and process tubing.
    - Chloride environments where stress-corrosion cracking is a concern, as the bulletin says it is relatively free from it.
    - Equipment that handles nitric acid and petroleum process streams.
  watch_out:
    - Heating at 540 to 760 °C can sensitise the alloy. Welding heat can do this, and the bulletin says to take care before pickling or other aggressive service.
    - For long-term high-temperature loading, the bulletin points to 800H or 800HT, not alloy 800.
    - Fumes and dust from cutting, grinding and welding carry the health classifications in the Special Metals safety data sheet.
    - No space use, outgassing, atomic-oxygen or radiation result was found for this alloy.
  verdict: Incoloy 800 is a corrosion-resistant, high-temperature iron-nickel-chromium alloy, with 250 MPa yield strength when annealed and use up to about 816 °C. It is heavy at 7.94 g/cm3, conducts heat poorly, and is sensitised by heating at 540 to 760 °C. For long-term creep loading the bulletin points to 800H or 800HT. No spacecraft use was found.
  recipe:
    line: Alloy 800 is an austenitic solid-solution alloy of nickel, chromium and iron, with aluminium and titanium also specified. Titanium nitrides, titanium carbides and chromium carbides normally appear in the microstructure (Special Metals bulletin). The composition limits are as printed in the bulletin's Table 2.
    parts:
      - name: Nickel
        symbol: Ni
        share: 30.0 to 35.0 %
        role: Keeps a ductile austenitic structure and gives resistance to chloride stress-corrosion cracking.
      - name: Chromium
        symbol: Cr
        share: 19.0 to 23.0 %
        role: Gives aqueous and heat resistance.
      - name: Iron
        symbol: Fe
        share: 39.5 % minimum
        role: Gives resistance to internal oxidation.
      - name: Aluminium
        symbol: Al
        share: 0.15 to 0.60 %
        role: Specified within 0.15 to 0.60 % in alloy 800; the bulletin lists it with titanium in the composition limits.
      - name: Titanium
        symbol: Ti
        share: 0.15 to 0.60 %
        role: Titanium nitrides and titanium carbides normally appear in the microstructure.
      - name: Carbon
        symbol: C
        share: 0.10 % maximum
        role: Limited to 0.10 % maximum in alloy 800; 800H has a higher carbon range, specified for higher creep and rupture strength.