Chromel Ni-10Cr (Chromel-P)

spore: profile
id: chromel
spore_version: 0.2
family: resistance-and-thermocouple-alloys
name: Chromel
abbreviation: Ni-10Cr (Chromel-P)
role: positive leg of Type K and Type E thermocouples
category: metals
type: nickel-superalloys
summary: |
  Chromel is the nickel-chromium alloy of about 90 % nickel and 10 % chromium, sold as Chromel-P (ASTM E-230, UNS N06010 in the Concept Alloys datasheet). It is the positive leg of the Chromel-Alumel (Type K) thermocouple. Kanthal's Thermothal P datasheet gives a density of 8.72 g/cm3, a melting point of 1430 °C and an electrical resistivity of 0.706 Ohm mm2/m at 20 °C. Its guide limit for bare wire is 900 °C for 1.00 mm wire, and Advent RM gives 1100 °C in oxidizing atmospheres. Annealed wire has a tensile strength of 95 ksi and an elongation of 35 % (Concept Alloys).
best_for: Sensing temperature as the positive leg of a base-metal thermocouple across about -200 °C to 1260 °C, with a chromium oxide scale that keeps it stable in air (Concept Alloys)
weakest_at: Use in reducing, alternating or vacuum atmospheres, which Kanthal excludes, and the sources give no corrosion rate; the mechanical data are only room-temperature and 500 °C points
identity:
  formula: Nickel-chromium alloy, nominal 90 Ni and 10 Cr; Kanthal Thermothal P nominal composition Ni balance, Cr 10.0, Si 0.5
  source: concept-chromel-p
  where: Nominal Composition line of the Concept Alloys Chromel-P datasheet (90 Ni, 10 Cr). The Kanthal Thermothal P chemical composition table gives Ni balance, Cr 10.0 and Si 0.5. Wikipedia describes the alloy as about 90 % nickel and 10 % chromium by weight.
  designations:
    - system: UNS
      code: N06010
      source: concept-chromel-p
      where: Industry Specifications line, UNS N06010
    - system: ASTM
      code: E-230
      note: thermocouple wire specification
      source: concept-chromel-p
      where: Industry Specifications line, ASTM E-230
    - system: Trade name
      code: Chromel-P
      note: trademark of Concept Alloys, Inc.
      source: concept-chromel-p
      where: Title line and footnote, Trademarked and Sold Exclusively by Concept Alloys
tags:
  environments: []
  stresses:
    - extreme-heat
  applications:
    - thermal-control
properties:
  - benchmark: density
    label: Density, Thermothal P (Kanthal)
    value: 8.72
    unit: g/cm3
    scope: material
    conditions:
      grade: Thermothal P (Kanthal), Ni90/Cr10 type
      temperature: not stated
    method: Value printed in a manufacturer datasheet
    status: ground
    source: kanthal-thermothal-p
    where: Physical properties section, Density
  - benchmark: density
    label: Density, Chromel-P (Concept Alloys)
    value: 8.73
    unit: g/cm3
    scope: material
    conditions:
      grade: Chromel-P, nominal 90 Ni 10 Cr
      temperature: not stated
    method: Value printed in a manufacturer datasheet
    status: ground
    note: Concept Alloys prints the same figure as specific gravity (8.73). Kept beside the Kanthal value; the two differ by 0.01 g/cm3.
    source: concept-chromel-p
    where: Typical Physical Property Data, Specific Gravity and Density (g/cm3) rows
  - benchmark: melting_point
    label: Melting point, Thermothal P (Kanthal)
    value: 1430
    unit: °C
    scope: material
    conditions:
      grade: Thermothal P (Kanthal)
      pressure: not stated
    method: Value printed in a manufacturer datasheet
    status: ground
    source: kanthal-thermothal-p
    where: Physical properties section, Melting point
  - benchmark: melting_point
    label: Approximate melting point, Chromel-P (Concept Alloys)
    value: 1427
    unit: °C
    scope: material
    conditions:
      grade: Chromel-P, nominal 90 Ni 10 Cr
    method: Approximate value printed in a manufacturer datasheet
    status: ground
    note: Printed as approximate; 2600 °F is printed beside it.
    source: concept-chromel-p
    where: Typical Physical Property Data, Approximate Melting Point row
  - benchmark: electrical_resistivity
    label: Electrical resistivity at 20 °C, Thermothal P (Kanthal)
    value: 0.706
    unit: Ω mm2/m
    scope: material
    conditions:
      grade: Thermothal P (Kanthal)
      temperature: 20 °C
    method: Value printed in a manufacturer datasheet
    status: ground
    source: kanthal-thermothal-p
    where: Physical properties section, Electrical resistivity (20°C)
  - benchmark: electrical_resistivity
    label: Nominal electrical resistivity at 20 °C, Chromel-P (Concept Alloys)
    value: 70.6
    unit: µΩ·cm
    scope: material
    conditions:
      grade: Chromel-P, nominal 90 Ni 10 Cr
      temperature: 20 °C
    method: Value printed in a manufacturer datasheet. The datasheet prints the unit as µΩ/cm3 in the cell; the paired row gives 425 Ω·mil2/ft, which is the same figure as 70.6 µΩ·cm, so µΩ·cm is used here.
    status: ground
    source: concept-chromel-p
    where: Typical Physical Property Data, Nominal Resistivity row (µΩ/cm3 cell, 70.6 at 20 °C)
  - benchmark: max_service_temp
    label: Guide maximum continuous temperature, bare wire 1.00 mm (Kanthal)
    value: 900
    unit: °C
    scope: material
    conditions:
      grade: Thermothal P (Kanthal)
      form: bare wire, diameter 1.00 mm
      environment: not stated; the page excludes reducing, alternating and vacuum atmospheres
    method: Guide value printed in a manufacturer datasheet
    status: ground
    note: The datasheet calls these guide values and does not say they apply in air.
    source: kanthal-thermothal-p
    where: Recommended maximum continuous operating temperature table, Bare wire row, column 1.00
  - benchmark: max_service_temp
    label: Upper operating limit in oxidizing atmospheres (Advent RM)
    value: 1100
    unit: °C
    scope: material
    conditions:
      grade: Ni90/Cr10 (Chromel)
      environment: oxidizing atmospheres
    method: Value printed on a supplier product page
    status: ground
    note: The Advent value is a supplier limit for oxidizing atmospheres and is not the same test as the Kanthal guide values.
    source: advent-chromel
    where: Ni90/Cr10 (Chromel) introduction section, maximum operating temperature
  - benchmark: thermal_conductivity
    label: Thermal conductivity at 100 °C, Thermothal P (Kanthal)
    value: 19.2
    unit: W/(m·K)
    scope: material
    conditions:
      grade: Thermothal P (Kanthal)
      temperature: 100 °C
      unit_in_source: W m-1 K-1
    method: Value printed in a manufacturer datasheet
    status: ground
    source: kanthal-thermothal-p
    where: Physical properties section, Thermal conductivity (100°C)
  - benchmark: specific_heat
    label: Specific heat capacity at 20 °C, Thermothal P (Kanthal)
    value: 0.448
    unit: kJ/(kg·K)
    scope: material
    conditions:
      grade: Thermothal P (Kanthal)
      temperature: 20 °C
      unit_in_source: kJ kg-1 K-1
    method: Value printed in a manufacturer datasheet
    status: ground
    source: kanthal-thermothal-p
    where: Physical properties section, Specific heat capacity (20°C)
  - benchmark: cte
    label: Coefficient of thermal expansion, 20 to 100 °C, Thermothal P (Kanthal)
    value: 17
    unit: ppm/K
    scope: material
    conditions:
      grade: Thermothal P (Kanthal)
      temperature: 20 to 100 °C
      unit_in_source: x 10-6/K
    method: Value printed in a manufacturer datasheet
    status: ground
    note: Concept Alloys prints 13.1 ppm/K over the same range. The two datasheets disagree by about 30 %, so both are kept.
    source: kanthal-thermothal-p
    where: Physical properties section, Coefficient of thermal expansion (20-100°C)
  - benchmark: cte
    label: Coefficient of thermal expansion, 20 to 100 °C, Chromel-P (Concept Alloys)
    value: 13.1
    unit: ppm/K
    scope: material
    conditions:
      grade: Chromel-P, nominal 90 Ni 10 Cr
      temperature: 20 to 100 °C
      unit_in_source: E-6 cm/cm/°C
    method: Value printed in a manufacturer datasheet
    status: ground
    note: Wikipedia prints 12.8 x 10-6/K at 20 to 1000 °C, a different range, and is not used here.
    source: concept-chromel-p
    where: Typical Physical Property Data, Temp. Coef. Of Expansion row
  - benchmark: elastic_modulus
    label: Young's modulus at 20 °C, Thermothal P (Kanthal)
    value: 200
    unit: GPa
    scope: material
    conditions:
      grade: Thermothal P (Kanthal)
      temperature: 20 °C
    method: Value printed in a manufacturer datasheet
    status: ground
    source: kanthal-thermothal-p
    where: Physical properties section, Young's modulus, 20 °C value
  - benchmark: yield_strength
    label: Yield strength, annealed, Chromel-P (Concept Alloys)
    value: 45
    unit: ksi
    scope: material
    conditions:
      grade: Chromel-P, nominal 90 Ni 10 Cr
      temper: annealed
      form: not stated
      temperature: not stated
    method: Typical value printed in a manufacturer datasheet
    status: ground
    source: concept-chromel-p
    where: Typical Mechanical Properties, Yield Strength, annealed (ksi)
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, annealed, Chromel-P (Concept Alloys)
    value: 95
    unit: ksi
    scope: material
    conditions:
      grade: Chromel-P, nominal 90 Ni 10 Cr
      temper: annealed
      form: not stated
      temperature: not stated
    method: Typical value printed in a manufacturer datasheet
    status: ground
    source: concept-chromel-p
    where: Typical Mechanical Properties, Tensile Strength, annealed (ksi)
  - benchmark: elongation
    label: Elongation, annealed, Chromel-P (Concept Alloys)
    value: 35
    unit: '%'
    scope: material
    conditions:
      grade: Chromel-P, nominal 90 Ni 10 Cr
      temper: annealed
      form: not stated
      temperature: not stated
    method: Typical value printed in a manufacturer datasheet
    status: ground
    source: concept-chromel-p
    where: Typical Mechanical Properties, Elongation, annealed (%)
  - benchmark: yield_strength
    label: Yield strength Rp0.2, 2.0 mm wire, room temperature, Thermothal P (Kanthal)
    value: 220
    unit: MPa
    scope: material
    conditions:
      grade: Thermothal P (Kanthal)
      form: wire, diameter 2.0 mm
      temperature: room temperature
      temper: not stated
    method: Value printed in a manufacturer datasheet
    status: ground
    source: kanthal-thermothal-p
    where: Mechanical properties, room temperature table, Yield strength (Rp0.2) for 2.0 mm wire
  - benchmark: ultimate_tensile_strength
    label: Tensile strength Rm, 2.0 mm wire, room temperature, Thermothal P (Kanthal)
    value: 580
    unit: MPa
    scope: material
    conditions:
      grade: Thermothal P (Kanthal)
      form: wire, diameter 2.0 mm
      temperature: room temperature
      temper: not stated
    method: Value printed in a manufacturer datasheet
    status: ground
    source: kanthal-thermothal-p
    where: Mechanical properties, room temperature table, Tensile strength (Rm) for 2.0 mm wire
  - benchmark: elongation
    label: Elongation A, 2.0 mm wire, room temperature, Thermothal P (Kanthal)
    value: 35
    unit: '%'
    scope: material
    conditions:
      grade: Thermothal P (Kanthal)
      form: wire, diameter 2.0 mm
      temperature: room temperature
      temper: not stated
    method: Value printed in a manufacturer datasheet
    status: ground
    source: kanthal-thermothal-p
    where: Mechanical properties, room temperature table, Elongation (A) for 2.0 mm wire
  - benchmark: hardness_vickers
    label: Hardness Hv, 2.0 mm wire, room temperature, Thermothal P (Kanthal)
    value: 140
    unit: HV
    scope: material
    conditions:
      grade: Thermothal P (Kanthal)
      form: wire, diameter 2.0 mm
      temperature: room temperature
    method: Value printed in a manufacturer datasheet
    status: ground
    note: Non-canonical property name; hardness_vickers is not in the canonical property file.
    source: kanthal-thermothal-p
    where: Mechanical properties, room temperature table, Hardness (Hv) for 2.0 mm wire
  - benchmark: yield_strength
    label: Yield strength Rp0.2 at 300 °C, Thermothal P (Kanthal)
    value: 244
    unit: MPa
    scope: material
    conditions:
      grade: Thermothal P (Kanthal)
      temperature: 300 °C
      temper: not stated
    method: Value printed in a manufacturer datasheet
    status: ground
    source: kanthal-thermothal-p
    where: Mechanical properties at elevated temperature table, row 300, column Rp0.2
  - benchmark: ultimate_tensile_strength
    label: Tensile strength Rm at 500 °C, Thermothal P (Kanthal)
    value: 563
    unit: MPa
    scope: material
    conditions:
      grade: Thermothal P (Kanthal)
      temperature: 500 °C
      temper: not stated
    method: Value printed in a manufacturer datasheet
    status: ground
    source: kanthal-thermothal-p
    where: Mechanical properties at elevated temperature table, row 500, column Rm
corrosion:
  - environment: Air at high temperature
    headline: Chromel is resistant to oxidation, and the bare wire can be used across its range in air.
    effect: Concept Alloys says the superior resistance of the alloys to oxidation allows the bare metals to be used throughout the useful range of -200 °C to +1260 °C, and that with proper protection the thermocouple can be used in almost any environment. No oxidation rate or weight gain is printed.
    rating: low
    conditions:
      environment: air
      basis: supplier datasheet; no test duration stated
    source: concept-chromel-p
    where: Opening paragraph of the datasheet
  - environment: Oxidizing atmospheres up to 1100 °C
    headline: Advent RM gives up to 1,100 °C in oxidizing atmospheres.
    effect: The Advent RM page gives the upper limit as up to 1,100 °C (2,010 °F) in oxidizing atmospheres. The page gives no oxidation rate and no test duration.
    rating: low
    conditions:
      environment: oxidizing atmospheres
      basis: supplier product page
    source: advent-chromel
    where: Ni90/Cr10 (Chromel) introduction section
  - environment: Reducing, alternating or vacuum atmospheres
    headline: Kanthal excludes reducing, alternating oxidizing and reducing, and vacuum service.
    effect: The Thermothal P datasheet says the material cannot be exposed to reducing or alternately oxidizing and reducing atmospheres or vacuum. It gives no corrosion rate, sulphur, chloride or humidity data for Chromel.
    rating: moderate
    conditions:
      environment: reducing, cycling or vacuum
      basis: manufacturer datasheet
    source: kanthal-thermothal-p
    where: Recommended maximum continuous operating temperature section, text below the table
risks:
  hazards:
    - text: Airgas nickel wire and rod SDS (approval 2-1-2016) lists GHS Hazard Classification as Not Classified, with no symbol or signal word. The sheet covers a nickel wire and rod product, not Chromel itself.
      ghs: []
      source: airgas-nickel-sds
      where: Section 2, GHS Hazard Classification line
    - text: PubChem GHS aggregate for nickel metal (the main constituent at about 90 %) includes H317, May cause an allergic skin reaction, Warning, reported by 100 % of notifiers. PubChem describes nickel metal, not the Chromel alloy.
      ghs: []
      source: pubchem-nickel-ghs
      where: GHS Classification section, H317 (100%) entry
    - text: PubChem GHS aggregate for nickel metal includes H351, Suspected of causing cancer, Warning, reported by 100 % of notifiers.
      ghs: []
      source: pubchem-nickel-ghs
      where: GHS Classification section, H351 (100%) entry
    - text: The Airgas nickel wire and rod SDS carries a California Proposition 65 statement that products may contain chemicals known to the State of California to cause cancer and birth defects.
      ghs: []
      source: airgas-nickel-sds
      where: Regulatory information section, California Proposition 65 line
  failure_risks:
    - mode: Attack in reducing, cycling or vacuum service
      trigger: Use in reducing or alternately oxidizing and reducing atmospheres, or in vacuum (Kanthal exclusion)
      consequence: The datasheet excludes these atmospheres and gives no corrosion rate, so the time to failure cannot be taken from it.
      severity: moderate
      source: kanthal-thermothal-p
      where: Recommended maximum continuous operating temperature section, text below the table
    - mode: Overheating of fine bare wire
      trigger: Operation of bare wire above the guide value for its diameter
      consequence: The Kanthal guide value for bare wire falls from 1050 °C at 3.26 mm to 710 °C at 0.25 mm, so fine wire has a lower limit than thick wire.
      severity: moderate
      source: kanthal-thermothal-p
      where: Recommended maximum continuous operating temperature table, Bare wire row
    - mode: Strength loss at temperature
      trigger: Sustained load or bending at 300 °C or above
      consequence: Kanthal prints Rp0.2 of 244 MPa at 300 °C and 217 MPa at 500 °C, and Rm of 594 MPa and 563 MPa at the same temperatures. No creep data are printed for Chromel.
      severity: low
      source: kanthal-thermothal-p
      where: Mechanical properties at elevated temperature table
  side_effects:
    - text: Welding and cutting of products containing chromium may produce hexavalent chromium. The Airgas sheet tells the user to follow OSHA rules for welding.
      affects: Handling of fume from grinding or welding
      source: airgas-nickel-sds
      where: Section on welding and cutting, hexavalent chromium line
  handling:
    - text: Keep bare wire below the Kanthal guide value for its diameter, and do not use it in reducing, alternating or vacuum atmospheres (Kanthal).
      source: kanthal-thermothal-p
      where: Recommended maximum continuous operating temperature section
    - text: Treat grinding or welding fume as possibly containing nickel and chromium compounds (Airgas sheet).
      source: airgas-nickel-sds
      where: Regulatory information and welding sections
  mitigations: []
uses:
  - application: thermal-control
    device: Type K thermocouple, positive leg
    example: Chromel is the positive leg of the Chromel-Alumel (Type K) thermocouple. Thermometrics gives Type K as commonly referenced for -200 °C to 1250 °C, and Concept Alloys gives a widely used range of -200 °C to +1260 °C for Chromel-P.
    source: thermometrics-typek
    where: Chromel Alumel section (positive leg); Type K temperature range section
  - application: thermal-control
    device: Type E thermocouple, positive conductor
    example: Wikipedia says the alloy is used to make the positive conductors of ANSI Type E (chromel-constantan) and K (chromel-alumel) thermocouples.
    source: wikipedia-chromel
    where: Lead paragraph
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: Canada
        share_percent: 3.6
        year: 2025
    recycling: 'USGS: nickel recovered from scrap accounted for approximately 60 % of apparent consumption in 2025.'
    substitutes:
      - 'USGS: low-nickel, duplex or ultrahigh-chromium stainless steels have been substituted for austenitic grades in construction; 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 against that printed total); Recycling; Substitutes
  - subject: Chromium
    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
    recycling: 'USGS: recycled chromium in reported stainless-steel scrap receipts accounted for 21 % of apparent consumption in 2025.'
    substitutes:
      - 'USGS: chromium has no substitute in stainless steel or in superalloys.'
    source: usgs-mcs2026-chromium
    where: World Mine Production and Reserves table, 2025e column (world total 51,000 thousand t; shares calculated by Space Mushroom against that printed total; Kazakhstan value is estimated by USGS); Recycling; Substitutes; Net import reliance 79 % in 2025e
documents:
  - title: 'Concept Alloys: Chromel-P Technical Data Sheet (rev. 12-23-09)'
    type: datasheet
    url: https://conceptalloys.com/wp-content/uploads/2013/10/Chromel-PGMVdatasheet091223.pdf
  - title: Thermothal P material datasheet (Kanthal)
    type: datasheet
    url: https://www.kanthal.com/en/products/datasheets/material-datasheets/wire/thermocouple-wire/thermothal-p/
  - title: 'Advent RM: Chromel (Ni90/Cr10) alloy page'
    type: datasheet
    url: https://www.advent-rm.com/en-gb/products/alloys/chromel
  - title: 'Thermometrics: Thermocouple Type K'
    type: datasheet
    url: https://thermometricscorp.com/typek.html
  - title: 'Wikipedia: Chromel'
    type: database
    url: https://en.wikipedia.org/wiki/Chromel
  - 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: 'PubChem: Nickel (CID 935), GHS classification'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/935/JSON?heading=GHS+Classification
  - title: Airgas Nickel Wire and Rod safety data sheet (approval 2-1-2016)
    type: sds
    url: https://www.airgas.com/msds/005727.pdf
    year: 2016
gaps:
  - Curie temperature is not stated by Kanthal. Thermometrics says nothing about the magnetic behaviour of chromel, so no magnetic transition is recorded.
  - 'Coefficient of thermal expansion disagrees between sources: Kanthal 17 ppm/K and Concept Alloys 13.1 ppm/K over the same 20 to 100 °C range. Both are kept, and no value was read for a third source.'
  - 'Temperature coefficient of resistance (Kanthal 300 x 10-6/K, Concept Alloys 3.2 x 10-4 per °C, both at 20 to 100 °C) was read but not recorded: the canonical property file has no name for it.'
  - No creep, creep-rupture or sustained-load data for Chromel were printed. Kanthal gives only elevated-temperature Rp0.2 and Rm values.
  - 'Corrosion: no sulphur, chloride, humidity or vacuum attack data and no corrosion rate in micrometres per year were printed by any fetched source.'
  - Outgassing, atomic-oxygen and radiation effects were not looked up for Chromel.
  - The PubChem GHS record is for nickel metal, not the Chromel alloy, and the Airgas SDS is for a nickel wire and rod product. No hazard classification for the 90/10 alloy itself was found.
  - Hardness and elevated-temperature values are listed under non-canonical names (hardness_vickers) or with the canonical name and a temperature in the label, because the canonical file has no separate entries for them.
  - Thermothal P is Kanthal's product name for a chromel-type positive leg. It is not listed as a designation because the Kanthal page does not call it the same grade as Chromel-P.
  - The Kanthal guide values do not state the atmosphere they assume, so they are not treated as an air limit.
  - Wikipedia gives a density of 8.5 g/cm3 and a resistivity of 0.706 µΩ·m, and 1420 °C. The density is not used because the two manufacturer datasheets agree at 8.72 and 8.73; the resistivity agrees with Kanthal, and the melting point is 10 °C below Kanthal.
  - The ASM Alloy Digest entry for Chromel-P (Hoskins Ni-69) was found in search results but is paywalled, so its values are not used.
  - Atomic weights of nickel and chromium were not read from a fetched page, so the recipe parts carry shares only.
  - No CAS number was recorded for the alloy.
  - No media were read for this profile.
sources:
  concept-chromel-p:
    title: Chromel-P Technical Data Sheet, Concept Alloys, Inc. (rev. 12-23-09)
    url: https://conceptalloys.com/wp-content/uploads/2013/10/Chromel-PGMVdatasheet091223.pdf
    year: 2009
    kind: datasheet
    license: Manufacturer datasheet (cited, not reproduced)
  kanthal-thermothal-p:
    title: Thermothal P material datasheet (Kanthal)
    url: https://www.kanthal.com/en/products/datasheets/material-datasheets/wire/thermocouple-wire/thermothal-p/
    year: 2024
    kind: datasheet
    license: Manufacturer datasheet (cited, not reproduced)
  advent-chromel:
    title: 'Advent RM: Chromel (Ni90/Cr10) alloy page'
    url: https://www.advent-rm.com/en-gb/products/alloys/chromel
    kind: web
    license: Supplier product page (cited, not reproduced)
  thermometrics-typek:
    title: Thermocouple Type K (Thermometrics)
    url: https://thermometricscorp.com/typek.html
    kind: web
    license: Supplier web page (cited, not reproduced)
  wikipedia-chromel:
    title: Chromel (Wikipedia)
    url: https://en.wikipedia.org/wiki/Chromel
    kind: web
    license: CC BY-SA 4.0 (cited, not reproduced)
  usgs-mcs2026-nickel:
    title: Mineral Commodity Summaries 2026, Nickel
    id: USGS MCS 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  usgs-mcs2026-chromium:
    title: Mineral Commodity Summaries 2026, Chromium
    id: USGS MCS 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-chromium.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  pubchem-nickel-ghs:
    title: 'PubChem: Nickel (CID 935), GHS Classification'
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/935/JSON?heading=GHS+Classification
    kind: database
    license: PubChem (public domain, NIH)
  airgas-nickel-sds:
    title: Safety Data Sheet, Nickel Wire and Rod (Airgas), SDS number 011-Ni Wire and Rod
    url: https://www.airgas.com/msds/005727.pdf
    year: 2016
    kind: datasheet
    license: Supplier safety data sheet (cited, not reproduced)
license: CC-BY-4.0
updated: '2026-10-26'
review:
  status: draft
  method: assistant
  checked_values: 22
  unreachable: 2
  caveats: 4
  note: 'Values were read by an AI assistant on 2026-10-26 from the pages named in each entry. Concept Alloys values are from the Chromel-P datasheet PDF. Kanthal values are from the Thermothal P datasheet read through a page summary. Advent RM and Thermometrics values come from fetched pages. Unreachable or not used in this run: the Thermometrics URL found in search returned 404 and the working page was used instead; the ASM Alloy Digest entry is paywalled. Caveats: the Kanthal guide values do not state their atmosphere; the thermal-expansion values disagree between Kanthal and Concept Alloys; the PubChem GHS record is for nickel metal; the Airgas SDS is for nickel wire and rod.'
story:
  risk_groups:
    - title: For people
      lead: Chromel is about 90 % nickel. The sources do not classify the 90/10 alloy itself, so the nickel and chromium raw materials are the better guide.
      level: 1
      verdict: Mixed classification
      points:
        - label: Nickel metal
          line: PubChem's GHS aggregate for nickel metal includes H317 (may cause an allergic skin reaction) and H351 (suspected of causing cancer), each reported by 100 % of notifiers.
        - label: Supplier classification
          line: The Airgas nickel wire and rod sheet is Not Classified under GHS and carries a California Proposition 65 statement for cancer and birth defects.
    - title: If it fails
      lead: The failure routes in the sources are atmosphere and temperature. The datasheets give limits but no failure rates.
      points:
        - label: Wrong atmosphere
          line: Kanthal excludes reducing, alternating oxidizing and reducing, and vacuum service. The sources give no corrosion rate for those cases.
        - label: Fine bare wire
          line: The Kanthal guide value for bare wire falls from 1050 °C at 3.26 mm to 710 °C at 0.25 mm.
    - title: Handling and storage
      points:
        - label: Keep it below the guide
          line: Keep bare wire below the Kanthal guide value for its diameter, and below the 1100 °C Advent oxidizing-air limit.
  why: Chromel is the positive leg of a base-metal thermocouple. Its nominal composition of 90 % nickel and 10 % chromium gives a stable calibrated thermoelectric pairing with Alumel for Type K sensing. Kanthal's Thermothal P datasheet gives a density of 8.72 g/cm3, a melting point of 1430 °C and a resistivity of 0.706 Ohm mm2/m at 20 °C. Its weak points in these sources are the atmosphere limits and the lack of creep or corrosion-rate data.
  uses:
    - where: Type K thermocouples
      line: Chromel is the positive leg of the Chromel-Alumel (Type K) thermocouple. Thermometrics gives a commonly referenced range of -200 °C to 1250 °C for Type K.
    - where: Type E thermocouples
      line: Wikipedia says the alloy makes the positive conductor of ANSI Type E (chromel-constantan) and Type K thermocouples.
  can_do:
    - label: Stay solid when hot
      value: 1430 °C melting point
      benchmark: melting_point
      line: The Kanthal datasheet gives a melting point of 1430 °C. Concept Alloys gives an approximate 1427 °C.
    - label: Work hot in air
      value: 1100 °C oxidizing-air limit
      benchmark: max_service_temp
      line: Advent RM gives up to 1,100 °C in oxidizing atmospheres. Kanthal's guide value for 1.00 mm bare wire is 900 °C.
    - label: Stay light
      value: 8.72 g/cm3
      benchmark: density
      line: Density is 8.72 g/cm3 in the Kanthal datasheet and 8.73 g/cm3 in the Concept Alloys datasheet.
  compare: 'This profile has no second thermocouple alloy read in the same run, so the compare rows use Chromel''s own figures: resistivity, the continuous temperature limit and thermal conductivity. Read them as Chromel''s values, not as a ranking against another metal.'
  compare_rows:
    - label: Electrical resistivity
      benchmark: electrical_resistivity
    - label: Max continuous temperature
      benchmark: max_service_temp
    - label: Thermal conductivity
      benchmark: thermal_conductivity
  handling:
    - Keep bare wire below the Kanthal guide value for its diameter (900 °C for 1.00 mm).
    - Do not use it in reducing, alternating or vacuum atmospheres (Kanthal).
    - Treat grinding or welding fume as possibly containing nickel and chromium compounds (Airgas sheet).
  good_for:
    - Positive leg of a Type K or Type E thermocouple, with a usable range of about -200 °C to 1260 °C (Concept Alloys).
    - 'Oxidation resistance in air: up to 1,100 °C in oxidizing atmospheres (Advent RM).'
    - Annealed wire with 95 ksi tensile strength and 35 % elongation (Concept Alloys).
  watch_out:
    - 'Atmosphere: Kanthal excludes reducing, alternating and vacuum service, and gives no corrosion rate.'
    - 'Strength falls with temperature: Rp0.2 of 244 MPa at 300 °C and 217 MPa at 500 °C (Kanthal). No creep data are printed.'
    - Thermal expansion differs by about 30 % between Kanthal (17 ppm/K) and Concept Alloys (13.1 ppm/K).
    - 'Hazard classification of the alloy itself was not found: the PubChem and Airgas data are for nickel metal and nickel wire.'
  verdict: Chromel-P is a nickel-chromium thermocouple leg rated to about 1100 °C in oxidizing air, with a melting point of 1430 °C and a density of 8.72 g/cm3. It is well documented as the positive leg of Type K, but the profile has no creep, corrosion-rate, outgassing or radiation values, and its atmosphere limits are the main constraint.
  recipe:
    line: Chromel is a two-element alloy of nickel and chromium, nominally 90 % nickel and 10 % chromium by mass (Concept Alloys, Wikipedia). The Kanthal datasheet gives Cr 10.0 %, Si 0.5 % and nickel as the balance.
    parts:
      - name: Nickel
        symbol: Ni
        share_percent: 90
        role: The matrix of the alloy (Concept Alloys nominal composition; Kanthal gives Ni as the balance).
      - name: Chromium
        symbol: Cr
        share_percent: 10
        role: Forms the chromium oxide scale that gives the alloy its oxidation resistance in air (Advent RM, Concept Alloys).