Monel K-500 K-500

spore: profile
id: monel-k500
spore_version: 0.2
family: nickel-alloys
name: Monel K-500
abbreviation: K-500
role: age-hardenable corrosion-resistant nickel-copper alloy for springs, fasteners and pump parts
category: metals
type: nickel-superalloys
summary: |
  Monel K-500 (UNS N05500) is a precipitation-hardening nickel-copper alloy with about 63 % nickel, 27 to 33 % copper, and small additions of aluminium and titanium that let it be age-hardened. Its density is 8.45 g/cm3 (ATI). Annealed rod and bar has a nominal tensile strength of 621 to 758 MPa, which rises to 896 to 1138 MPa when aged (Smiths Metal Centres). It is virtually non-magnetic and its corrosion resistance is close to that of Monel 400, but the age-hardened condition is more prone to stress corrosion cracking.
best_for: Springs, fasteners and pump parts that need much higher strength than Monel 400 with similar corrosion resistance, in a virtually non-magnetic alloy
weakest_at: Stress corrosion cracking in the age-hardened condition, which is the condition that gives the high strength
identity:
  formula: Ni 63.0 % min (with Co), Cu 27 to 33 %, Al 2.30 to 3.15 %, Ti 0.35 to 0.85 %, Fe 2.0 % max, Mn 1.5 % max, Si 0.5 % max, C 0.18 % max, S 0.01 % max; age-hardened by Ni3(Ti,Al) particles
  source: ati-k500
  where: Composition table, bar and billet section of the ATI product page (Ni min 63.0, Cu 27-33, Al 2.30-3.15, Ti 0.35-0.85, Fe max 2.0, Mn max 1.5, Si max 0.50, C max 0.18, S max 0.01). Ni3(Ti,Al) particles from the Monel article on Wikipedia.
  designations:
    - system: UNS
      code: N05500
      source: ati-k500
      where: Page heading 'ATI K-500 Nickel-Based Alloy; UNS N05500'
    - system: EN
      code: '2.4375'
      source: aircraftmaterials-k500
      where: Other row of the Specifications table, 'W.Nr. 2.4375'
    - system: BS
      code: NA18
      note: BS3072 NA18 for sheet, plate and strip; BS3076 NA18 for bar and wire
      source: aircraftmaterials-k500
      where: Specifications table, Sheet and Bar rows
    - system: AMS
      code: '4676'
      source: ati-k500
      where: Product specifications list, AMS 4676
    - system: ASTM
      code: B865
      source: austral-wright
      where: Chemical composition table heading 'ASTM B865 - Bar, rod, wire, forgings & forging stock'
    - system: Trade name
      code: Monel K-500
      source: austral-wright
      where: Page heading 'Monel K-500 UNS-N05500'
tags:
  environments: []
  applications:
    - mechanisms
properties:
  - benchmark: density
    label: Density, bar and billet
    value: 8.45
    unit: g/cm3
    scope: material
    conditions:
      section: bar and billet
      temperature: not stated
      unit_in_source: 0.306 lb/in3
    method: Value printed on a manufacturer product page
    status: ground
    source: ati-k500
    where: Physical properties, Density row, bar and billet section
  - benchmark: density
    label: Density at 20 °C, metric table
    value: 8440
    unit: kg/m3
    scope: material
    conditions:
      temperature: 20 °C
      unit_in_source: 8,440 kg/m³ @ 20°C
    method: Value printed in a stockist's metric properties table
    status: ground
    source: austral-wright
    where: Physical Properties table (metric), Density row
  - benchmark: density
    label: Density, stockist listing
    value: 8.44
    unit: g/cm3
    scope: material
    conditions:
      temperature: not stated
      unit_in_source: 0.305 lb/in3
    method: Value printed on a stockist's product page
    status: ground
    source: bibus-k500
    where: Density heading
  - benchmark: melting_point
    label: Melting range, metric table
    value: 1315
    value_high: 1350
    bound: range
    unit: °C
    scope: material
    conditions:
      unit_in_source: 1315-1350°C
    method: Range printed in a stockist's metric properties table
    status: ground
    source: austral-wright
    where: Physical Properties table, Melting Range row
  - benchmark: melting_point
    label: Melting range, imperial table
    value: 2400
    value_high: 2460
    bound: range
    unit: °F
    scope: material
    conditions:
      condition: not stated
    method: Range printed in a distributor's physical properties table
    status: ground
    source: hightempmetals-k500
    where: Physical Properties table, Melting Range row
  - benchmark: elastic_modulus
    label: Modulus of elasticity, tension, 20 °C
    value: 179
    unit: GPa
    scope: material
    conditions:
      temperature: 20 °C
    method: Value printed in a stockist's metric properties table
    status: ground
    source: austral-wright
    where: Physical Properties table, Modulus of Elasticity (tension) row
  - benchmark: elastic_modulus
    label: Modulus of elasticity, tension, imperial table
    value: 26
    unit: 10^6 psi
    scope: material
    conditions:
      temperature: not stated
    method: Value printed in a distributor's physical properties table
    status: ground
    source: hightempmetals-k500
    where: Physical Properties table, row Modulus of Elasticity, Tension
  - benchmark: shear_modulus
    label: Modulus of rigidity (torsion), 20 °C
    value: 65.5
    unit: GPa
    scope: material
    conditions:
      temperature: 20 °C
    method: Value printed in a stockist's metric properties table
    status: ground
    source: austral-wright
    where: Physical Properties table, Modulus of Rigidity (torsion) row
  - benchmark: poisson_ratio
    label: Poisson's ratio
    value: 0.32
    unit: '-'
    scope: material
    conditions:
      temperature: not stated
    method: Value printed in a stockist's metric properties table
    status: ground
    source: austral-wright
    where: Physical Properties table, Poisson's Ratio row
  - benchmark: thermal_conductivity
    label: Thermal conductivity at 20 °C, metric
    value: 17.5
    unit: W/m °C
    scope: material
    conditions:
      temperature: 20 °C
      unit_in_source: W/m. °C
    method: Value printed in a stockist's metric properties table
    status: ground
    source: austral-wright
    where: Physical Properties table, Thermal Conductivity row
  - benchmark: thermal_conductivity
    label: Thermal conductivity at 70 °F, annealed
    value: 121
    unit: Btu-in/(hr·ft²·°F)
    scope: material
    conditions:
      temperature: 70 °F
      condition: annealed before test (table footnote a)
      unit_in_source: Btu-in-hr-sq ft-°F
    method: Value printed in a distributor's thermal properties table
    status: ground
    source: hightempmetals-k500
    where: Thermal Properties table, row 70, column Thermal Conductivity
  - benchmark: cte
    label: Coefficient of thermal expansion at 20 °C
    value: 13.7
    unit: 10-6/°C
    scope: material
    conditions:
      temperature: 20 °C
      unit_in_source: 13.7 x 10-6 / °C
    method: Value printed in a stockist's metric properties table
    status: ground
    source: austral-wright
    where: Physical Properties table, Coefficient of Thermal Expansion row
  - benchmark: cte
    label: Mean linear expansion at 200 °F, annealed
    value: 7.6
    unit: in/in-°F x 10^-6
    scope: material
    conditions:
      temperature: 200 °F
      condition: annealed before test (table footnote a)
    method: Value printed in a distributor's thermal properties table
    status: ground
    source: hightempmetals-k500
    where: Thermal Properties table, row 200, column Mean Linear Expansion
  - benchmark: specific_heat
    label: Specific heat at 20 °C
    value: 419
    unit: J/kg °C
    scope: material
    conditions:
      temperature: 20 °C
    method: Value printed in a stockist's metric properties table
    status: ground
    source: austral-wright
    where: Physical Properties table, Thermal Capacity (Specific Heat) row
  - benchmark: electrical_resistivity
    label: Electrical resistivity at 20 °C
    value: 0.615
    unit: µΩ·m
    scope: material
    conditions:
      temperature: 20 °C
      unit_in_source: microhm.m
    method: Value printed in a stockist's metric properties table
    status: ground
    source: austral-wright
    where: Physical Properties table, Electrical Resistivity row
  - benchmark: curie_temperature
    label: Curie temperature
    value: -65
    unit: °C
    scope: material
    conditions:
      condition: not stated
    method: Value printed in a stockist's metric properties table
    status: ground
    source: austral-wright
    where: Physical Properties table, Curie Temperature row
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, rod and bar, hot-finished and annealed
    value: 621
    value_high: 758
    bound: range
    unit: MPa
    scope: material
    conditions:
      form: rod and bar
      temper: hot-finished, annealed
      basis: nominal range for product sizes
    method: Nominal range printed in a manufacturer datasheet
    status: ground
    source: smith-datasheet
    where: Mechanical Properties table, row Hot-Finished, Annealed, column Tensile Strength MPa
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, rod and bar, hot-finished, annealed and aged
    value: 896
    value_high: 1138
    bound: range
    unit: MPa
    scope: material
    conditions:
      form: rod and bar
      temper: hot-finished, annealed and age-hardened
      basis: nominal range for product sizes
    method: Nominal range printed in a manufacturer datasheet
    status: ground
    source: smith-datasheet
    where: Mechanical Properties table, row Hot-Finished, Annealed and Aged, column Tensile Strength MPa
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, rod and bar, hot-finished and aged for maximum properties
    value: 965
    value_high: 1310
    bound: range
    unit: MPa
    scope: material
    conditions:
      form: rod and bar
      temper: hot-finished and age-hardened
      basis: nominal properties for material age-hardened to produce maximum properties (table footnote)
    method: Nominal range printed in a manufacturer datasheet
    status: ground
    source: smith-datasheet
    where: Mechanical Properties table, row Hot-Finished, Aged, column Tensile Strength MPa
  - benchmark: yield_strength
    label: Yield strength, rod and bar, hot-finished and annealed
    value: 276
    value_high: 414
    bound: range
    unit: MPa
    scope: material
    conditions:
      form: rod and bar
      temper: hot-finished, annealed
      basis: nominal range for product sizes
    method: Nominal range printed in a manufacturer datasheet
    status: ground
    source: smith-datasheet
    where: Mechanical Properties table, row Hot-Finished, Annealed, column Yield Strength MPa
  - benchmark: yield_strength
    label: Yield strength, rod and bar, hot-finished, annealed and aged
    value: 586
    value_high: 827
    bound: range
    unit: MPa
    scope: material
    conditions:
      form: rod and bar
      temper: hot-finished, annealed and age-hardened
      basis: nominal range for product sizes
    method: Nominal range printed in a manufacturer datasheet
    status: ground
    source: smith-datasheet
    where: Mechanical Properties table, row Hot-Finished, Annealed and Aged, column Yield Strength MPa
  - benchmark: elongation
    label: Elongation, rod and bar, hot-finished, annealed and aged
    value: 20
    value_high: 35
    bound: range
    unit: '%'
    scope: material
    conditions:
      form: rod and bar
      temper: hot-finished, annealed and age-hardened
      basis: nominal range, printed as 35-20
    method: Nominal range printed in a manufacturer datasheet
    status: ground
    source: smith-datasheet
    where: Mechanical Properties table, row Hot-Finished, Annealed and Aged, column Elongation %
  - benchmark: max_service_temp
    label: Temperature up to which high tensile properties hold after age-hardening
    value: 650
    unit: °C
    scope: material
    conditions:
      condition: after age-hardening
      basis: product statement, not a test result
      unit_in_source: 1200 °F
    method: Temperature stated in the introduction of a manufacturer datasheet
    status: ground
    source: smith-datasheet
    where: Introduction paragraph, 'high tensile properties up to 650°C (1200°F) after age-hardening'
corrosion:
  - environment: Seawater
    headline: Low corrosion rates in seawater, with pitting possible in stagnant or slow-moving water.
    effect: A supplier page calls the corrosion rate in seawater low and says pitting may occur in stagnant or low-velocity seawater, but that the pitting rate eventually slows after the first attack. No rate, temperature or time is given.
    rating: low
    conditions:
      basis: qualitative statement on a supplier page
    source: corrosionmaterials-k500
    where: Resistance to Corrosion section, seawater sentences
  - environment: Sour gas containing hydrogen sulphide
    headline: Resists hydrogen sulphide, and is certified for sour service.
    effect: A supplier page says resistance to hydrogen sulphide makes the alloy useful in sour gas, with no concentration or temperature given. Langley Alloys says its K-500 is certified to NACE MR0175 / ISO 15156-3, and a test of age-hardened sheet in saturated H2S is reported by another supplier but not entered here.
    rating: low
    conditions:
      basis: qualitative statement; hardness limits of the standard not read
    source: corrosionmaterials-k500
    where: Resistance to Corrosion section, H2S sentence
  - environment: Age-hardened condition in some environments
    headline: The age-hardened condition is more prone to stress corrosion cracking than Monel 400.
    effect: The Monel article on Wikipedia says age-hardened K-500 has a greater tendency toward stress corrosion cracking than alloy 400 in some environments. The supplier page says the age-hardened alloy can experience stress corrosion cracking in certain environments and names none. Corrosion resistance otherwise matches Monel 400.
    rating: moderate
    conditions:
      condition: age-hardened
      basis: literature and supplier statements; no test rate given
    source: wikipedia-monel
    where: Monel article, Monel K-500 paragraph
risks:
  hazards:
    - text: Special Metals' safety data sheet for wrought nickel alloys, which lists Monel among its products, says the alloys in massive form have no known toxicological properties other than allergic reactions in people sensitive to the metals. Fume or dust released during melting, grinding, cutting or welding carries the classified hazards.
      ghs:
        - H317
        - H334
        - H335
        - H350
        - H361d
        - H372
        - H373
      source: special-metals-sds
      where: Section 2.1 Classification (CLP), list of codes; the sheet is a general sheet and does not name K-500
    - text: The same sheet's exposure-limit list gives nickel as Category 1 (causes cancer in man) and a respiratory and skin sensitizer on the German DFG list.
      ghs: []
      source: special-metals-sds
      where: Exposure limits section, Germany DFG list, Nickel row
  failure_risks:
    - mode: Stress corrosion cracking of age-hardened material
      trigger: Use of the age-hardened (highest-strength) condition in some environments
      consequence: Cracking under stress in environments where the age-hardened alloy is more susceptible than Monel 400. The sources give no threshold.
      severity: moderate
      source: wikipedia-monel
      where: Monel article, Monel K-500 paragraph
    - mode: Pitting in stagnant or slow seawater
      trigger: Stagnant or low-velocity seawater
      consequence: Localised pits. The supplier says the pitting rate slows after the initial attack.
      severity: low
      source: corrosionmaterials-k500
      where: Resistance to Corrosion section, seawater sentences
  side_effects:
    - text: 'Strength depends strongly on the condition: the nominal tensile range is 621 to 758 MPa when hot-finished and annealed, and 896 to 1138 MPa when hot-finished, annealed and aged.'
      affects: Strength and choice of heat treatment
      source: smith-datasheet
      where: Mechanical Properties table
  handling:
    - text: Specify the condition (annealed, cold-drawn, or age-hardened), because the nominal tensile and yield ranges are higher in the aged rows of the datasheet than in the annealed rows.
      source: smith-datasheet
      where: Mechanical Properties table
    - text: Keep fume and dust out of the breathing zone during melting, grinding, cutting and welding, since the Special Metals sheet names these as the hazard source.
      source: special-metals-sds
      where: Section 2.1 Classification (CLP), note on fume and dust
    - text: For sour service, use material certified to NACE MR0175 / ISO 15156-3 (Langley Alloys says its K-500 is certified) and check the hardness limits in the standard before use.
      source: langley-k500
      where: Opening paragraph, certification sentence
  mitigations: []
uses:
  - application: mechanisms
    device: Springs, fasteners and valve parts
    example: Smiths Metal Centres lists fasteners and springs, pump and valve components, oil well drill collars, impellers and marine engineering applications as uses of Monel K500.
    source: smith-datasheet
    where: Key Features and Applications section
  - application: mechanisms
    device: Pump shafts, impellers and drill collars
    example: The Monel article on Wikipedia lists pump shafts and impellers, oil-well drill collars, steam-turbine blades, condenser tubes and marine hardware as typical K-500 uses.
    source: wikipedia-monel
    where: Monel article, Monel K-500 paragraph
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 about 60 % of apparent consumption in 2025, and most secondary nickel was stainless-steel scrap.'
    substitutes:
      - 'USGS: 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 (world total 3,900,000 t; shares calculated by Space Mushroom from Indonesia 2,600,000, Philippines 270,000 and Russia 200,000); Recycling; Substitutes
  - subject: Copper (mine production, the second element at 27 to 33 %)
    producers:
      - country: Chile
        share_percent: 23
        year: 2025
      - country: Congo (Kinshasa)
        share_percent: 13.9
        year: 2025
      - country: Peru
        share_percent: 11.7
        year: 2025
    critical_lists: []
    substitutes: []
    source: usgs-mcs2026-copper
    where: World Mine and Refinery Production and Reserves table, mine production 2025e (world total 23,000 thousand t; shares calculated by Space Mushroom from Chile 5,300, Congo (Kinshasa) 3,200 and Peru 2,700)
documents:
  - title: ATI K-500 Nickel-Based Alloy, product page (composition, density, mechanical properties)
    type: datasheet
    url: https://www.atimaterials.com/Products/ati-k-500
  - title: Monel K500 Product Datasheet, Smiths Metal Centres (nominal mechanical property ranges)
    type: datasheet
    url: https://www.smithmetal.com/pdf/nickel/monel-k500.pdf
    year: 2023
  - title: Monel Alloy K-500 product page, Bibus Metals (density)
    type: datasheet
    url: https://metals.bibus.com/ch-en/products/itm/nickel-alloy-K-500
  - title: Monel K-500 UNS N05500, Austral Wright Metals technical data (metric physical properties, equivalent specifications)
    type: datasheet
    url: https://www.australwright.com.au/technical-data/alloys/high-performance-alloys/n05500-monel-k-500/
  - title: Nickel Alloy K-500 / Monel K-500, Aircraft Materials (specifications)
    type: datasheet
    url: https://www.aircraftmaterials.com/data/nickel/K-500.html
  - title: Monel K-500 Technical Data, High Temp Metals (physical properties, thermal table, magnetic characteristics)
    type: datasheet
    url: https://hightempmetals.com/techdata/hitempMonelK500data.php
  - title: Safety Data Sheet, Special Metals wrought nickel alloys including Monel (EU CLP, revised 2016)
    type: sds
    url: https://www.specialmetals.com/documents/msds.pdf
    year: 2016
  - title: Monel, Wikipedia (K-500 paragraph)
    type: database
    url: https://en.wikipedia.org/wiki/Monel
  - title: Alloy K-500, Corrosion Materials (resistance to corrosion)
    type: database
    url: https://corrosionmaterials.com/alloys/alloy-k-500/
  - title: What is 2.4375, Langley Alloys technical resources (Monel K-500)
    type: database
    url: https://www.langleyalloys.com/technical-resources/what-is-2-4375/
  - 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: Copper'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-copper.pdf
    year: 2026
gaps:
  - No spacecraft, rocket or satellite use of Monel K-500 was found. The NASA 1967 cryogenic spring report (NTRS 19670000349) was read and does not mention K-500, and the other searches returned only vendor pages for Monel in general.
  - The Special Metals product page and K-500 datasheet could not be reached (404, 503 and an HTML page instead of a PDF). The Ulbrich wire datasheet redirected to a file that returned an XML error, and MatWeb, MakeItFrom, Ulprospector and the ASM Alloy Digest returned 403 or paywall pages, so none of them is used. Values come from ATI, Smiths, Austral Wright, High Temp Metals and Bibus instead.
  - 'Composition conflicts between sources: carbon is 0.18 % max in ATI, Smiths and Austral Wright but 0.25 % max in Aircraft Materials, H.P. Alloys and Bibus; manganese is 0.20 % max on the Titanium.com table against 1.5 % max elsewhere; the Titanium.com table also prints sulphur as 01 %. The ATI values are used.'
  - The EN chemical name NiCu30Al and the AFNOR designation NU30AT were seen only in search summaries, not on a page read in this run, so they are not listed. The BS 3076 entry is not listed separately from BS 3072.
  - Electrical conductivity (2.8 %IACS, Austral Wright) and magnetic permeability (1.0018, High Temp Metals) are not entered because their benchmark names are not in the canonical list. Hardness (Brinell and Rockwell, Smiths) is also not entered for the same reason.
  - Physical constants from the two distributor tables are not checked against the manufacturer's own datasheet, which was not reachable. Imperial values are kept in the units printed.
  - Corrosion rates in millimetres or micrometres per year were not found. The supplier page gives qualitative statements only, and the NACE MR0175 hardness limits were not read.
  - Radiation, outgassing, atomic oxygen, cold welding and vacuum behaviour were not searched for this alloy.
  - The hazard entries come from a general Special Metals sheet for wrought nickel alloys, not a K-500 sheet. Monel is one of its covered products, but K-500 is not named.
  - Supply shares list only the top three producers for nickel and copper, and nickel's critical-mineral status was not confirmed from a list.
sources:
  ati-k500:
    title: ATI K-500 Nickel-Based Alloy, product page (composition, density, bar and plate mechanical properties)
    url: https://www.atimaterials.com/Products/ati-k-500
    kind: datasheet
    license: Manufacturer product page (cited, not reproduced)
  smith-datasheet:
    title: Monel K500 Product Datasheet, Smiths Metal Centres (2023), nickel-copper alloy UNS N05500
    id: UNS N05500
    url: https://www.smithmetal.com/pdf/nickel/monel-k500.pdf
    year: 2023
    kind: datasheet
    license: Distributor datasheet (cited, not reproduced)
  bibus-k500:
    title: Monel Alloy K-500, Bibus Metals product page
    url: https://metals.bibus.com/ch-en/products/itm/nickel-alloy-K-500
    kind: datasheet
    license: Stockist product page (cited, not reproduced)
  austral-wright:
    title: Monel K-500 UNS N05500, Austral Wright Metals technical data
    id: UNS N05500; DIN 2.4375; BS NA18
    url: https://www.australwright.com.au/technical-data/alloys/high-performance-alloys/n05500-monel-k-500/
    kind: datasheet
    license: Stockist technical data (cited, not reproduced)
  aircraftmaterials-k500:
    title: Nickel Alloy K-500 / Monel K-500, Aircraft Materials
    id: W.Nr. 2.4375; BS3072 NA18; ASTM B 865; AMS 4676; NACE MR-01-75
    url: https://www.aircraftmaterials.com/data/nickel/K-500.html
    kind: datasheet
    license: Supplier technical page (cited, not reproduced)
  hightempmetals-k500:
    title: Monel K-500 Technical Data, High Temp Metals (copyright 2015)
    url: https://hightempmetals.com/techdata/hitempMonelK500data.php
    kind: datasheet
    license: Supplier technical page (cited, not reproduced); no test standard is cited on the page
  special-metals-sds:
    title: Safety Data Sheet, Special Metals wrought nickel alloys including Monel (EU CLP/REACH, revised 30 November 2016)
    url: https://www.specialmetals.com/documents/msds.pdf
    kind: datasheet
    license: Manufacturer safety data sheet (cited, not reproduced)
  wikipedia-monel:
    title: Monel, Wikipedia (Monel K-500 paragraph)
    url: https://en.wikipedia.org/wiki/Monel
    kind: web
    license: CC BY-SA 4.0 (cited, not reproduced)
  corrosionmaterials-k500:
    title: Alloy K-500, Corrosion Materials
    url: https://corrosionmaterials.com/alloys/alloy-k-500/
    kind: web
    license: Supplier web page (cited, not reproduced)
  langley-k500:
    title: What is 2.4375, Langley Alloys technical resources
    url: https://www.langleyalloys.com/technical-resources/what-is-2-4375/
    kind: web
    license: Supplier web page (cited, not reproduced)
  usgs-mcs2026-nickel:
    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-mcs2026-copper:
    title: 'Mineral Commodity Summaries 2026: Copper'
    id: USGS MCS 2026, February 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-copper.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: 23
  unreachable: 6
  caveats: 5
  note: 'Values were read by an AI assistant on 2026-10-26 from the pages and PDFs named in each entry. Unreachable: the Special Metals K-500 datasheet, the Ulbrich wire datasheet, MatWeb, MakeItFrom, Ulprospector and the ASM Alloy Digest. Caveats: the physical constants are from stockists, not the manufacturer; the mechanical ranges are nominal; the Smiths and High Temp Metals tables give no test standard; no space use was found; corrosion is qualitative only.'
story:
  risk_groups:
    - title: For people
      lead: The alloy in massive form is said to cause allergic reactions only in sensitive people. The classified hazard comes from fume and dust made while melting, grinding, cutting or welding.
      level: 1
      verdict: Hazard in fume and dust
      points:
        - label: Solid alloy
          line: The Special Metals sheet says the alloys in massive form have no known toxicological properties other than allergy in people sensitive to the metals.
        - label: Fume and dust
          line: The same sheet classifies fume and dust with H317, H334, H335, H350, H361d, H372 and H373 codes. Nickel is a Category 1 carcinogen on the German DFG list.
    - title: If it fails
      lead: 'The sources describe two failure routes for this alloy: stress corrosion cracking in the age-hardened state, and pitting in stagnant seawater.'
      points:
        - label: Stress corrosion
          line: Age-hardened K-500 has a greater tendency toward stress corrosion cracking than alloy 400 in some environments, according to Wikipedia.
        - label: Seawater pits
          line: Pitting can start in stagnant or slow seawater, but the supplier says the pitting rate slows after the first attack.
    - title: Handling and storage
      points:
        - label: Temper
          line: Choose the condition for the strength you need. The aged rows of the Smiths table sit well above the annealed rows.
        - label: Sour service
          line: Use material certified to NACE MR0175 / ISO 15156-3 for sour service. Langley Alloys says its K-500 is certified, and the hardness limits of the standard still apply.
  why: Monel K-500 is a nickel-copper alloy that is harder and stronger than Monel 400 because it can be age-hardened. It keeps the corrosion resistance of Monel 400, is virtually non-magnetic, and is used for springs, fasteners and pump parts. Its density is 8.45 g/cm3, and it conducts heat far less well than copper, at 17.5 W/m °C at 20 °C.
  uses:
    - where: Springs and fasteners
      line: Smiths Metal Centres lists fasteners and springs among the applications of Monel K500, alongside pump and valve components and marine engineering.
    - where: Pumps, drilling and marine parts
      line: Oil-well drill collars, pump shafts and impellers are typical uses named by Wikipedia.
    - where: Space hardware
      line: No spacecraft, rocket or satellite use of Monel K-500 was found in the sources read for this profile.
  can_do:
    - label: Strength when annealed
      value: 621 to 758 MPa tensile
      benchmark: ultimate_tensile_strength
      line: Hot-finished and annealed rod and bar has a nominal tensile strength of 621 to 758 MPa and a yield strength of 276 to 414 MPa (Smiths).
    - label: Strength when aged
      value: 896 to 1138 MPa tensile
      benchmark: ultimate_tensile_strength
      line: Hot-finished, annealed and aged rod and bar has a nominal tensile strength of 896 to 1138 MPa and a yield strength of 586 to 827 MPa.
    - label: Density
      value: 8.45 g/cm3
      benchmark: density
      line: ATI prints a density of 8.45 g/cm3 for bar and billet, and Austral Wright prints 8,440 kg/m3 at 20 °C.
    - label: Melting
      value: 1315 to 1350 °C
      benchmark: melting_point
      line: The stockist's metric table gives a melting range of 1315 to 1350 °C, and the imperial table gives 2400 to 2460 °F.
    - label: Stiffness
      value: 179 GPa
      benchmark: elastic_modulus
      line: The tension modulus is 179 GPa at 20 °C, and the imperial table gives 26 x 10^6 psi.
    - label: Magnetism
      value: virtually non-magnetic
      benchmark: curie_temperature
      line: Smiths says the alloy is virtually non-magnetic. Austral Wright gives a Curie temperature of -65 °C.
  compare: Monel K-500 gets its strength from age hardening, so its tensile range depends on the temper and the product form, far more than on the composition. Copper, the site's conductor profile, conducts heat and current far better, and the two alloys serve different roles, so read the table rows as examples, not a ranking.
  compare_rows:
    - label: Density
      benchmark: density
    - label: Thermal conductivity
      benchmark: thermal_conductivity
    - label: Thermal expansion
      benchmark: cte
  recipe:
    line: Monel K-500 is an alloy, not a compound. It is nickel and copper with small additions of aluminium and titanium (ATI composition table), and it is age-hardened by Ni3(Ti,Al) particles that form on heat treatment (Wikipedia).
    parts:
      - name: Nickel plus cobalt
        symbol: Ni
        share: 63.0 % min
        role: The base metal of the alloy. The ATI table sets nickel with cobalt at a minimum of 63.0 %.
      - name: Copper
        symbol: Cu
        share: 27 to 33 %
        role: Forms the nickel-copper matrix that gives the alloy its Monel corrosion behaviour.
      - name: Aluminium
        symbol: Al
        share: 2.30 to 3.15 %
        role: Combines with titanium to form the Ni3(Ti,Al) particles that harden the alloy on ageing.
      - name: Titanium
        symbol: Ti
        share: 0.35 to 0.85 %
        role: Part of the Ni3(Ti,Al) precipitate used for age hardening.
  good_for:
    - Springs, fasteners and pump parts that need high strength with Monel-type corrosion resistance.
    - Virtually non-magnetic parts where a nickel-copper alloy is specified.
    - Sour gas and seawater service, where the supplier reports low corrosion rates and resistance to hydrogen sulphide.
  watch_out:
    - Age-hardened material is more prone to stress corrosion cracking than Monel 400 (Wikipedia).
    - Strength depends strongly on the temper, so annealed and aged ranges differ by a wide margin.
    - Fume and dust from melting, grinding, cutting and welding carry the classified hazards (Special Metals).
    - No spacecraft use was found in the sources read, and the mechanical values are nominal ranges, not design minima.
  verdict: Monel K-500 is an age-hardenable nickel-copper alloy that keeps Monel-type corrosion resistance with much higher strength than Monel 400. Its density is 8.45 g/cm3 and it is virtually non-magnetic. The age-hardened state is more prone to stress corrosion cracking, and no spacecraft use was found in the sources read.