spore: profile
id: inconel-706
spore_version: 0.2
family: nickel-alloys
name: Inconel 706
role: precipitation-hardened turbine disc superalloy
category: metals
type: nickel-superalloys
summary: |
  Alloy 706 (UNS N09706, also sold as Inconel 706) is a precipitation-hardened nickel-iron-chromium superalloy. CarTech gives its density as 0.2920 lb/in3 in the age-hardened condition and describes its high strength as lasting from cryogenic temperatures to about 1200°F (650°C). It is used for gas-turbine discs and shafts, and CarTech says it is easier to fabricate than Alloy 718.
best_for: Large forged gas-turbine discs and shafts that need strength up to about 1200°F (650°C) and easier fabrication than Alloy 718.
weakest_at: The datasheet gives no strength values above its service range, and pitting and stress corrosion cracking are named as concerns in harsh drilling environments.
identity:
  formula: 'Precipitation-hardenable nickel-iron-chromium superalloy. Type analysis as printed by CarTech (nominal unless noted): Nickel 39.00 to 44.00 %, Chromium 14.50 to 17.50 %, Columbium plus Tantalum 2.50 to 3.30 %, Titanium 1.50 to 2.00 %, Aluminum 0.40 % maximum, Carbon 0.06 % maximum, Iron balance.'
  source: cartech706
  where: Identification and Type Analysis tables, page 1 of the CarTech 706 Alloy datasheet
  designations:
    - system: UNS
      code: N09706
      source: cartech706
      where: Identification, UNS Number (printed N09706)
    - system: AMS
      code: '5701'
      source: cartech706
      where: Other Information, Applicable Specifications (printed AMS 5701)
    - system: AMS
      code: '5702'
      source: cartech706
      where: Other Information, Applicable Specifications (printed AMS 5702)
    - system: AMS
      code: '5703'
      source: cartech706
      where: Other Information, Applicable Specifications (printed AMS 5703)
    - system: AMS
      code: '5605'
      source: azom706
      where: Other Designations list (printed AMS 5605, equivalent to Inconel 706)
    - system: AMS
      code: '5606'
      source: azom706
      where: Other Designations list (printed AMS 5606, equivalent to Inconel 706)
    - system: Trade name
      code: Inconel 706
      source: aircraft706
      where: Page title and designation line (printed Inconel 706 tradename)
    - system: Trade name
      code: Pyromet Alloy 706
      source: cartech706
      where: Corrosion Resistance and Workability text (printed Pyromet Alloy 706)
tags:
  applications:
    - propulsion-and-tanks
properties:
  - benchmark: density
    label: Density, age-hardened condition
    value: 0.292
    unit: lb/in3
    scope: material
    conditions:
      condition: age-hardened (precipitation-hardened)
      basis: typical value as printed; the datasheet says its data are typical or average values
    method: Typical value in the CarTech physical properties table
    status: ground
    source: cartech706
    where: Page 2, Physical Properties, Density, Age-hardened row (printed 0.2920 lb/in³)
  - benchmark: density
    label: Density, annealed condition
    value: 0.291
    unit: lb/in3
    scope: material
    conditions:
      condition: annealed
      basis: typical value as printed; the datasheet says its data are typical or average values
    method: Typical value in the CarTech physical properties table
    status: ground
    source: cartech706
    where: Page 2, Physical Properties, Density, Annealed row (printed 0.2910 lb/in³)
  - benchmark: specific_heat
    value: 0.106
    unit: Btu/lb/°F
    scope: material
    conditions:
      basis: mean specific heat as printed; the temperature range is not stated
    method: Typical value in the CarTech physical properties table
    status: ground
    source: cartech706
    where: Page 2, Physical Properties, Mean Specific Heat (printed 0.1060 Btu/lb/°F)
  - benchmark: thermal_conductivity
    value: 87
    unit: BTU-in/hr/ft2/°F
    scope: material
    conditions:
      basis: as printed; the temperature is not stated
    method: Typical value in the CarTech physical properties table
    status: ground
    source: cartech706
    where: Page 2, Physical Properties, Thermal Conductivity (printed 87.00 BTU-in/hr/ft²/°F)
  - benchmark: poissons_ratio
    value: 0.382
    unit: '-'
    scope: material
    conditions:
      basis: as printed; the temperature is not stated
    method: Typical value in the CarTech physical properties table
    status: ground
    source: cartech706
    where: Page 2, Physical Properties, Poisson's Ratio (printed 0.382)
  - benchmark: melting_point
    value: 2440
    value_high: 2500
    bound: range
    unit: °F
    scope: material
    conditions:
      basis: melting range as printed
    method: Melting range in the CarTech physical properties table
    status: ground
    source: cartech706
    where: Page 2, Physical Properties, Melting Range (printed 2440 to 2500 °F)
  - benchmark: electrical_resistivity
    value: 592
    unit: ohm-cir-mil/ft
    scope: material
    conditions:
      basis: as printed; the temperature is not stated
    method: Typical value in the CarTech physical properties table
    status: ground
    source: cartech706
    where: Page 2, Physical Properties, Electrical Resistivity (printed 592.0 ohm-cir-mil/ft)
  - benchmark: max_service_temp
    value: 1200
    unit: °F
    scope: material
    conditions:
      basis: 'service statement: high strength from cryogenic temperatures to about 1200°F (650°C); the datasheet prints no strength values above this range'
    method: Service range stated in the datasheet description, not a test result
    status: ground
    source: cartech706
    where: Page 1, General Information, Description (printed about 1200°F (650°C))
  - benchmark: density
    value: 8.05
    unit: g/cm3
    scope: material
    conditions:
      basis: no condition stated on the page
    method: Physical Properties table on the AZoM page (the page also prints 0.291 lb/in3 in imperial units)
    status: ground
    source: azom706
    where: Physical Properties table, Density row (printed 8.05 g/cm³)
  - benchmark: melting_point
    value: 1360
    unit: °C
    scope: material
    conditions:
      basis: no condition stated on the page
    method: Physical Properties table on the AZoM page (imperial 2480 °F printed alongside)
    status: ground
    source: azom706
    where: Physical Properties table, Melting point row (printed 1360°C)
  - benchmark: elastic_modulus
    value: 210
    unit: GPa
    scope: material
    conditions:
      condition: precipitation hardened
      test: dynamic method, as printed
    method: Mechanical Properties table on the AZoM page; the test method is printed in its condition column
    status: ground
    source: azom706
    where: Mechanical Properties table, Modulus of elasticity row (printed 210 GPa)
  - benchmark: yield_strength
    value: 383
    unit: MPa
    scope: material
    conditions:
      strain: at strain 0.200%, as printed
      temperature: not stated
    method: Mechanical Properties table on the AZoM page
    status: ground
    source: azom706
    where: Mechanical Properties table, Yield strength row (printed 383 MPa)
  - benchmark: ultimate_tensile_strength
    value: 757
    unit: MPa
    scope: material
    conditions:
      basis: no condition stated on the page
    method: Mechanical Properties table on the AZoM page
    status: ground
    source: azom706
    where: Mechanical Properties table, Tensile strength row (printed 757 MPa)
  - benchmark: cte
    value: 13.46
    unit: µm/m°C
    scope: material
    conditions:
      temperature_range: 24 to 100 °C, as printed (24-100°C)
    method: Thermal Properties table on the AZoM page; the imperial value 7.478 µin/in°F is printed alongside
    status: ground
    source: azom706
    where: Thermal Properties table, Thermal expansion co-efficient row (printed 13.46 µm/m°C)
  - benchmark: thermal_conductivity
    value: 12.5
    unit: W/mK
    scope: material
    conditions:
      basis: no condition stated on the page
    method: Thermal Properties table on the AZoM page (imperial 86.8 BTU in/hr.ft².°F printed alongside)
    status: ground
    source: azom706
    where: Thermal Properties table, Thermal conductivity row (printed 12.5 W/mK)
  - benchmark: ultimate_tensile_strength
    value: 109.8
    unit: ksi
    scope: material
    conditions:
      form: sheet, cold rolled
      condition: solution annealed
    method: Typical Mechanical Properties table on the Aircraft Materials page; no test temperature is stated
    status: ground
    source: aircraft706
    where: Typical Mechanical Properties table, Alloy 706 Sheet Cold Rolled row, Solution Annealed (printed 109.8 Ksi)
  - benchmark: yield_strength
    value: 55.5
    unit: ksi
    scope: material
    conditions:
      form: sheet, cold rolled
      condition: solution annealed
    method: Typical Mechanical Properties table on the Aircraft Materials page; no test temperature is stated
    status: ground
    source: aircraft706
    where: Typical Mechanical Properties table, Alloy 706 Sheet Cold Rolled row, Solution Annealed (printed 55.5 Yield Strength)
  - benchmark: elongation
    value: 47
    unit: '%'
    scope: material
    conditions:
      form: sheet, cold rolled
      condition: solution annealed
    method: Typical Mechanical Properties table on the Aircraft Materials page; no test temperature is stated
    status: ground
    source: aircraft706
    where: Typical Mechanical Properties table, Alloy 706 Sheet Cold Rolled row, Solution Annealed (printed 47 Elongation)
  - benchmark: elastic_modulus
    value: 205
    value_high: 215
    bound: range
    unit: GPa
    scope: material
    conditions:
      basis: page title says Annealed; no test temperature or method is stated
    method: Properties list on the Modulus Metal page, printed as Young's modulus
    status: ground
    source: modulus706
    where: Properties list, Modulus of elasticity row (printed 205 – 215 GPa)
  - benchmark: size_change_during_aging
    value: 0.09
    unit: '%'
    scope: material
    conditions:
      direction: contraction
      process: two-step aging heat treatment described on the page
    method: Statement in the CarTech heat treatment section, not a separate test
    status: ground
    source: cartech706
    where: Page 6, Heat Treatment (printed Size change during aging = 0.09% contraction)
  - benchmark: ultimate_tensile_strength
    value: 1170
    unit: MPa
    scope: material
    conditions:
      basis: AMS 5703 specified tensile value quoted in the paper; large forged trial disks
    method: Specification value quoted in the paper, which says the trial disk tensile properties were acceptable against it; not a measured value of one lot
    status: ground
    source: shibata2001
    where: 'Section Trial Manufacture of Large Size Disks, first paragraph (printed TS : 1170 MPa in AMS 5703); the paper compares Alloy 706 with Alloy 718 in its Introduction'
  - benchmark: yield_strength
    value: 930
    unit: MPa
    scope: material
    conditions:
      basis: 0.2% offset yield value in AMS 5703, as quoted in the paper; large forged trial disks
    method: Specification value quoted in the paper; not a measured value of one lot
    status: ground
    source: shibata2001
    where: 'Section Trial Manufacture of Large Size Disks, first paragraph (printed 0.2%YS : 930 MPa)'
  - benchmark: elongation
    value: 12
    unit: '%'
    scope: material
    conditions:
      basis: El. value in AMS 5703, as quoted in the paper; large forged trial disks
    method: Specification value quoted in the paper; not a measured value of one lot
    status: ground
    source: shibata2001
    where: 'Section Trial Manufacture of Large Size Disks, first paragraph (printed El. : 12%)'
corrosion:
  - environment: Sea water
    headline: Sea water rates Moderate on CarTech's comparative four-level scale.
    effect: CarTech's corrosion table prints Moderate for sea water. The table is for comparison only, and the datasheet says corrosion testing is recommended because temperature, concentration, pH, aeration, crevices and surface finish all change the result.
    rating: moderate
    conditions:
      scale: CarTech four-level comparative scale, printed word Moderate
      temperature: not stated
    source: cartech706
    where: Page 2, Corrosion Resistance table
  - environment: Nitric acid
    headline: Nitric acid rates Moderate on CarTech's comparative four-level scale.
    effect: CarTech's corrosion table prints Moderate for nitric acid. No concentration or temperature is given, so the rating cannot be tied to a test.
    rating: moderate
    conditions:
      scale: CarTech four-level comparative scale, printed word Moderate
      concentration: not stated
    source: cartech706
    where: Page 2, Corrosion Resistance table
  - environment: Sulfuric acid
    headline: Sulfuric acid is rated Restricted by CarTech, the weakest word on its scale.
    effect: CarTech prints Restricted for sulfuric acid. This profile maps Restricted to severe for the site's rating field, because the datasheet offers no finer scale. Other datasheets for this alloy were not opened, so no test value is given.
    rating: severe
    conditions:
      scale: CarTech four-level comparative scale, printed word Restricted, mapped to severe
      concentration: not stated
    source: cartech706
    where: Page 2, Corrosion Resistance table
  - environment: Humidity and salt spray (NaCl)
    headline: CarTech rates humidity and salt spray Excellent, the top word on its scale.
    effect: CarTech prints Excellent for humidity and for salt spray. This profile maps Excellent to none for the rating field, meaning no corrosion expected at this comparative level. The datasheet says testing is still recommended.
    rating: none
    conditions:
      scale: CarTech four-level comparative scale, printed word Excellent, mapped to none
      exposure: not stated beyond the test names
    source: cartech706
    where: Page 2, Corrosion Resistance table
  - environment: Harsh oil-drilling environments with pitting and stress corrosion cracking
    headline: CarTech says Alloy 706 was superior to Cr-Mn-N austenitic stainless steels in laboratory tests where pitting and stress corrosion cracking are concerns.
    effect: The datasheet names pitting and stress corrosion cracking as the concerns in drilling collars and logging housings, and says the alloy 'has been shown to be superior in laboratory tests'. No corrosion rate or test duration is printed.
    rating: unknown
    conditions:
      basis: laboratory comparison against Cr-Mn-N stainless steels, as described by the datasheet; test duration not stated
    source: cartech706
    where: Page 1, Applications, oil and gas paragraph
risks:
  hazards:
    - text: PubChem's GHS record for elemental nickel (CID 935) gives the signal word Danger and lists skin and respiratory sensitisation, suspected genetic defects, carcinogenicity, possible harm to fertility, and organ damage from repeated or prolonged exposure. Alloy 706 contains nickel, but the record is for the nickel element, not for this alloy.
      ghs:
        - H317
        - H334
        - H341
        - H350
        - H351
        - H360F
        - H372
        - H412
      source: pubchem-nickel
      where: Safety and Hazards, GHS Classification (CID 935, Nickel)
    - text: No safety data sheet for the Alloy 706 mill product itself was found in the sources opened, so the alloy is not separately classified here.
      ghs: []
      source: pubchem-nickel
      where: Not applicable; the alloy has no hazard record in the sources opened
  failure_risks:
    - mode: Loss of strength above the service range
      trigger: Exposure above about 1200°F (650°C)
      consequence: CarTech claims high strength only from cryogenic temperatures to about 1200°F (650°C), and prints no strength values above that range. Strength above the range is not established by any source opened.
      severity: moderate
      source: cartech706
      where: Page 1, General Information, Description
    - mode: Dimensional change during aging
      trigger: Two-step aging heat treatment
      consequence: The datasheet prints a 0.09% contraction during aging, so finished dimensions must allow for it.
      severity: low
      source: cartech706
      where: Page 6, Heat Treatment
    - mode: Pitting and stress corrosion cracking in harsh drilling environments
      trigger: Drilling environments named by the datasheet
      consequence: The datasheet names pitting and stress corrosion cracking as the concerns and reports laboratory superiority over Cr-Mn-N stainless steels. It gives no failure data, so the margin in service is not known.
      severity: moderate
      source: cartech706
      where: Page 1, Applications, oil and gas paragraph
  mitigations:
    - text: CarTech recommends corrosion testing for any application, because temperature, concentration, pH, impurities, aeration, velocity, crevices, deposits, metallurgical condition, stress, surface finish and dissimilar metal contact all change the result.
      source: cartech706
      where: Page 2, Corrosion Resistance table, Important Note
  handling:
    - text: 'Treat machining dust and fume as nickel-bearing material: the PubChem record for nickel lists carcinogenicity and sensitisation, so the alloy''s dust should not be breathed.'
      source: pubchem-nickel
      where: Safety and Hazards, GHS Classification (CID 935)
    - text: CarTech says the alloy can be machined in either the annealed or the age-hardened condition, and that its machinability is better than Alloy 718's.
      source: cartech706
      where: Page 6, Workability, Machinability
uses:
  - application: propulsion-and-tanks
    device: Gas-turbine discs and shafts (aerospace and industrial)
    example: CarTech says the alloy 'has been used for turbine discs in large industrial gas turbines as well as aerospace turbines', and that other turbine engine parts include shafts, cases, mounts and fasteners.
    source: cartech706
    where: Page 1, Applications
  - application: propulsion-and-tanks
    device: Large forged land-based gas-turbine discs
    example: Shibata and co-authors of the Japan Steel Works say Alloy 706 'has recently been used for land based turbines' and is suitable for large forgings such as an industrial gas turbine disk.
    source: shibata2001
    where: Introduction, first two paragraphs
  - application: propulsion-and-tanks
    device: Aerospace and land-based gas-turbine parts
    example: Aircraft Materials says 'The main uses of Alloy 706 are for aerospace and land base gas turbine parts and components.'
    source: aircraft706
    where: Page text, uses statement
supply:
  - subject: Nickel
    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: New Caledonia
        share_percent: 3.6
        year: 2025
      - country: Canada
        share_percent: 3.6
        year: 2025
      - country: China
        share_percent: 3.1
        year: 2025
      - country: Brazil
        share_percent: 1.8
        year: 2025
      - country: Australia
        share_percent: 1.2
        year: 2025
      - country: United States
        share_percent: 0.3
        year: 2025
    critical_lists:
      - list: USGS 2025 List of Critical Minerals (nickel is named in the final list)
        listed: true
      - list: 'EU critical raw materials list (Regulation (EU) 2024/1252): the Commission page says copper and nickel are strategic raw materials but do not meet the critical thresholds'
        listed: false
    recycling: 'USGS: ''nickel recovered from scrap accounted for approximately 60% of apparent consumption'' in 2025.'
    substitutes:
      - 'USGS: titanium alloys can substitute for nickel or nickel-base alloys in corrosive environments.'
    source: usgs-nickel-2026
    where: World Mine Production and Reserves table, 2025e column (world total 3,900,000 t, rounded); shares calculated by Space Mushroom as each printed value over that total, to one decimal place. Recycling paragraph. Substitutes paragraph.
documents:
  - title: CarTech 706 Alloy datasheet (Pyromet Alloy 706, edition 9/1/06)
    type: datasheet
    url: https://www.carpentertechnology.com/hubfs/7407324/Material%20Saftey%20Data%20Sheets/706.pdf
    year: 2006
  - title: 'Aircraft Materials: Nickel Alloy 706 / Inconel 706 (UNS N09706) technical data sheet'
    type: datasheet
    url: https://aircraftmaterials.com/data/nickel/706.html
    year: 2026
  - title: Shibata et al., Superalloy 706 large forgings by ESR (Superalloys 718, 625, 706 and Various Derivatives, TMS 2001)
    type: paper
    url: https://www.tms.org/superalloys/10.7449/2001/Superalloys_2001_161_172.pdf
    year: 2001
  - title: 'USGS Mineral Commodity Summaries 2026: Nickel'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf
    year: 2026
  - title: PubChem compound record, Nickel (CID 935), GHS classification
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/Nickel
    year: 2026
gaps:
  - No space, vacuum, radiation or flight data for Alloy 706 were found in the sources opened. The uses above are ground and aviation turbine service.
  - Measured elevated-temperature tensile and yield values were not recovered. The 2022 open-access low-cycle fatigue paper at 650 °C returned HTTP 403, and the MatWeb Special Metals datasheets also returned HTTP 403.
  - The CarTech datasheet's Typical Mechanical Properties table (pages 3 and 4) is an image with no text layer, so its values are not recorded.
  - CarTech's modulus of elasticity and mean CTE rows are printed in power-of-ten form, so they were left out. Modulus is taken from AZoM and Modulus Metal, and CTE from AZoM only.
  - Modulus Metal prints thermal expansion in a unit that looks wrong (µstrain/°C), so it was not recorded. Its yield and tensile values sit under an Annealed heading and conflict with the Aircraft Materials solution-annealed sheet values, so they were not recorded.
  - AZoM's composition table prints titanium differently from CarTech (AZoM maximum 0.40 %, CarTech 1.50 to 2.00 %). CarTech is used for composition.
  - 'Magnetic permeability (1.0100 Mu at 200 Oe) and the Curie temperature (printed as less than -100 °F) are printed by CarTech but not recorded: the first has a non-standard unit and the second is a bound, not a value.'
  - No ASTM, EN, DIN or W.Nr. designation was printed for this grade in the sources opened, so none is listed.
  - No abundance figure for nickel was in the sources opened; the USGS nickel summary covers production, reserves and recycling only.
  - Hazard data are for elemental nickel (PubChem CID 935), not for the alloy. No alloy safety data sheet was found.
  - Creep and rupture strength were not found in an open source.
  - size_change_during_aging is not a canonical property name, so a short snake_case name is used.
  - Heat-treatment schedules and the hot working range are printed by CarTech (pages 5 and 6) but are described in words here, not recorded as numbers.
  - Corrosion ratings are CarTech's four comparative words mapped to none, low, moderate, severe or unknown. The datasheet calls the scale comparative only.
sources:
  cartech706:
    title: CarTech 706 Alloy (Pyromet Alloy 706) datasheet, edition 9/1/06
    id: CRS Holdings Inc., Carpenter Technology; UNS N09706
    url: https://www.carpentertechnology.com/hubfs/7407324/Material%20Saftey%20Data%20Sheets/706.pdf
    year: 2006
    kind: datasheet
    license: manufacturer datasheet, cited not reproduced
  aircraft706:
    title: Nickel Alloy 706 / Inconel 706 (UNS N09706) technical data sheet, Aircraft Materials
    id: UNS N09706
    url: https://aircraftmaterials.com/data/nickel/706.html
    year: 2026
    kind: datasheet
    license: web page, cited not reproduced
  carpenter706:
    title: 'Carpenter Technology alloy finder: Alloy 706'
    id: CarTech alloy finder, UNS N09706
    url: https://www.carpentertechnology.com/alloy-finder/706
    year: 2026
    kind: datasheet
    license: manufacturer web page, cited not reproduced
  modulus706:
    title: INCONEL 706, Annealed (N09706), material data sheet, Modulus Metal
    id: UNS N09706; AMS 5701 to 5703, 5605, 5606 as printed
    url: https://www.modulusmetal.com/inconel-706-annealed-nickel-chromium-alloy-material-data-sheet/
    year: 2026
    kind: datasheet
    license: stockist web page, cited not reproduced
  azom706:
    title: Super Alloy Inconel 706 (UNS N09706), AZoM
    id: AZoM article 7697
    url: https://www.azom.com/article.aspx?ArticleID=7697
    year: 2013
    kind: web
    license: web article, cited not reproduced
  shibata2001:
    title: Superalloy 706 large forgings by ESR (Shibata, Takahashi, Taira and Kure, Japan Steel Works), in Superalloys 718, 625, 706 and Various Derivatives
    id: TMS 2001, pp. 161-172, doi:10.7449/2001/Superalloys_2001_161_172
    url: https://www.tms.org/superalloys/10.7449/2001/Superalloys_2001_161_172.pdf
    year: 2001
    kind: paper
    license: TMS conference paper, cited not reproduced
  usgs-nickel-2026:
    title: 'Mineral Commodity Summaries 2026: Nickel'
    id: USGS MCS 2026, February 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  usgs-critical-2025:
    title: About the 2025 List of Critical Minerals (USGS)
    id: Final 2025 List of Critical Minerals, November 2025
    url: https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals
    year: 2025
    kind: web
    license: public domain (USGS)
  ec-crm:
    title: Critical raw materials (European Commission), Regulation (EU) 2024/1252
    id: Regulation (EU) 2024/1252
    url: https://single-market-economy.ec.europa.eu/sectors/raw-materials/areas-specific-interest/critical-raw-materials_en
    year: 2024
    kind: web
    license: European Commission web page
  pubchem-nickel:
    title: PubChem compound record, Nickel (CID 935), GHS classification
    id: CID 935
    url: https://pubchem.ncbi.nlm.nih.gov/compound/Nickel
    year: 2026
    kind: database
    license: public domain (NCBI)
license: CC-BY-4.0
updated: '2026-11-02'
review:
  status: draft
  method: assistant
  checked_values: 23
  unreachable: 3
  caveats: 3
  note: Written by an AI assistant on 2026-11-02 from the CarTech datasheet (text layer read with pdftotext), the AZoM, Aircraft Materials, Modulus Metal and Shibata et al. (Superalloys 2001) pages, and the USGS and PubChem records. Alloy 718 comparisons come from the Shibata et al. Introduction and CarTech's own statements. MatWeb and ScienceDirect returned HTTP 403 and were not used.
story:
  recipe:
    line: Alloy 706 is a nickel-iron-chromium alloy that is age-hardened by coherent precipitates, gamma prime and gamma double prime, formed in its austenitic nickel matrix during heat treatment (Shibata et al. describe both). Large ingots for forgings are made by vacuum induction melting followed by electroslag remelting. CarTech gives a solution treatment and a two-step precipitation (aging) schedule, which this profile describes in words only.
    parts:
      - name: Nickel
        symbol: Ni
        share: 39.00 to 44.00 %
        role: A major element of the alloy, forming the austenitic matrix that the gamma prime and gamma double prime precipitates harden (Shibata et al.).
      - name: Chromium
        symbol: Cr
        share: 14.50 to 17.50 %
        role: A major element. The sources opened describe its nominal range but not its individual role in this grade.
      - name: Columbium plus tantalum (niobium)
        symbol: Nb+Ta
        share: 2.50 to 3.30 %
        role: Shibata et al. give a tensile strength relation that depends on the titanium and niobium contents.
      - name: Titanium
        symbol: Ti
        share: 1.50 to 2.00 %
        role: Shibata et al. give a tensile strength relation that depends on the titanium and niobium contents.
      - name: Iron
        symbol: Fe
        share: balance
        role: The balance of the composition. Shibata et al. say Alloy 706 has more iron than Alloy 718.
  risk_groups:
    - title: For people
      verdict: Alloy not classified; nickel metal is
      lead: No source opened classifies the Alloy 706 mill product itself. The PubChem record for nickel, its main element, carries hazard codes for sensitisation, carcinogenicity and organ toxicity.
      points:
        - label: Dust and fume
          line: If machining or welding makes dust or fume from the alloy, treat it as nickel-bearing. PubChem lists carcinogenicity and sensitisation for nickel metal, so dust should be controlled.
        - label: Data gap
          line: No safety data sheet for the alloy was found in the sources opened, so the hazard entries describe nickel and not this grade.
    - title: In service
      verdict: Strength claim stops near 1200°F
      lead: The datasheet gives a service range and names two concerns. It prints no strength values beyond the service range.
      points:
        - label: Service range
          line: CarTech claims high strength from cryogenic temperatures to about 1200°F (650°C). No strength values are printed above that range.
        - label: Corrosion
          line: CarTech names pitting and stress corrosion cracking as concerns in harsh oil-drilling environments, and reports laboratory superiority over Cr-Mn-N stainless steels without a numerical rate.
        - label: Aging distortion
          line: The datasheet prints a 0.09% contraction during aging, so finished dimensions must allow for it.
    - title: Handling and processing
      points:
        - label: Machining
          line: CarTech says the alloy machines more easily than Alloy 718 in either the annealed or the age-hardened condition.
        - label: Welding
          line: CarTech says Alloy 706 has excellent weldability and resistance to post-weld cracking, and that its welding procedures are the same as those for Alloy 718.
  why: Alloy 706 (UNS N09706, also sold as Inconel 706) is a precipitation-hardened nickel-iron-chromium superalloy for hot rotating parts such as gas-turbine discs. CarTech describes it as keeping high strength from cryogenic temperatures to about 1200°F (650°C), with characteristics similar to Alloy 718 but better fabricability, and as suitable for larger ingots and forgings than many superalloys. That combination is why it is chosen for large turbine forgings where ease of making the part matters.
  uses:
    - where: Gas-turbine discs and shafts
      line: CarTech says the alloy has been used for turbine discs in large industrial gas turbines and in aerospace turbines. Other turbine engine parts it lists are shafts, cases, mounts and fasteners.
    - where: Land-based turbines
      line: Shibata et al. of the Japan Steel Works say Alloy 706 has recently been used for land-based turbines and is suited to large forgings such as an industrial gas turbine disk.
    - where: Oil and gas drilling (candidate use)
      line: CarTech calls the alloy a candidate for non-magnetic drilling parts such as drill collars and logging housings, where pitting and stress corrosion cracking are concerns. The datasheet describes this as a candidate, not as a service history.
  can_do:
    - label: High-temperature strength
      line: Hold high strength from cryogenic temperatures to about 1200°F (650°C), per the CarTech datasheet.
    - label: Machining and welding
      line: Be machined and welded more easily than Alloy 718, per CarTech, which also reports excellent resistance to strain-age cracking of weldments.
    - label: Large forgings
      line: Be made as large forged disks. The Shibata et al. trial disks were made by vacuum induction melting and electroslag remelting, and the paper says their tensile properties met the AMS 5703 values quoted there (1170 MPa tensile strength and 930 MPa yield strength).
    - label: Room-temperature strength
      line: Reach a tensile strength of 757 MPa and a yield strength of 383 MPa in one AZoM table, but that table prints no test condition for the tensile value.
  compare: Alloy 706 is a nickel-iron-chromium sibling of Alloy 718. Shibata et al. say it was developed from Alloy 718 with no molybdenum, less niobium, aluminium, chromium, nickel and carbon, and more titanium and iron, and that this gives it better segregation behaviour, hot workability and machinability. CarTech says that in the annealed condition the alloy is softer and easier to deform than Alloy 718. The three compare rows below use the density, tensile strength and modulus rows of this profile. Their sources do not share one test condition, so compare the rows by the condition printed beside each value.
  compare_rows:
    - label: Density, age-hardened
      benchmark: density
    - label: Tensile strength
      benchmark: ultimate_tensile_strength
    - label: Elastic modulus
      benchmark: elastic_modulus
  handling:
    - No safety data sheet for the alloy itself was found, so the hazard information is for nickel metal from PubChem.
    - Treat machining dust and fume as nickel-bearing material, because the nickel record lists carcinogenicity and sensitisation.
    - CarTech recommends corrosion testing for any use, because temperature, concentration, pH and surface finish all change corrosion results.
    - Follow the heat-treatment schedule in the CarTech datasheet for the product form you buy. This profile does not reproduce the schedule.
  good_for:
    - Large forged hot-section discs that need strength up to about 1200°F (650°C), per CarTech.
    - Parts that must be machined or welded more easily than Alloy 718, per CarTech.
  watch_out:
    - The sources do not share one test condition. AZoM prints tensile and yield values with no test condition, and the Aircraft Materials values are for cold-rolled, solution-annealed sheet.
    - Composition differs between sources for titanium. CarTech prints 1.50 to 2.00 %, and AZoM prints a maximum of 0.40 %. This profile uses CarTech.
    - No flight, vacuum or radiation data were found. The uses listed are ground and aviation turbine service.
  verdict: Alloy 706 is a sound choice for large hot-section forgings that need strength up to about 1200°F (650°C) and easier fabrication than Alloy 718. The evidence is manufacturer datasheets and one conference paper. No test data above the service range were recovered.