spore: profile
id: titanium
spore_version: '0.2'
family: titanium-alloys
name: Titanium (commercially pure, grades 1 to 4)
abbreviation: CP Ti
role: unalloyed corrosion-resistant metal for tubing and plumbing
category: metals
type: titanium
summary: |
  Commercially pure titanium is unalloyed titanium sold as ASTM grades 1 to 4, which differ in their limits on oxygen, iron, carbon, nitrogen and hydrogen. ATI prints a density of 4.51 g/cm3 for each grade, and a minimum yield strength of 138 MPa for grade 1 against 483 MPa for grade 4 in bar and billet. NASA's White Sands test facility tested grade 2 rods and found that they burn in oxygen-enriched gas.
best_for: Corrosion-resistant tubing and plumbing where strength is secondary; grade 1 is the most ductile (ATI minimum elongation 24 %)
weakest_at: Strength in the lower grades (grade 1 has a 138 MPa minimum yield strength, ATI), and ignition in oxygen-enriched gas (NASA)
identity:
  formula: 'Ti (unalloyed titanium, 99 to 99.5 % Ti overall). Composition maxima in weight % from the ATI tables: grade 1 Fe 0.20, O 0.18, C 0.08, N 0.03, H 0.015; grade 2 Fe 0.30, O 0.25, C 0.08, N 0.03, H 0.015; grade 3 Fe 0.30, O 0.35, C 0.08, N 0.03 to 0.05, H 0.015; grade 4 Fe 0.50, O 0.40, C 0.08, N 0.05, H 0.015; titanium balance in each grade'
  source: ati-cp1
  where: Composition tables of the ATI CP grade 1 to 4 pages (maxima, Ti balance). The 99 to 99.5 % Ti overall range is from the Orlowski de Garcia et al. paper (redalyc-cbers).
  designations:
    - system: UNS
      code: R50250
      note: CP grade 1
      source: ati-cp1
      where: Designations block, UNS line
    - system: UNS
      code: R50400
      note: CP grade 2
      source: ati-cp2
      where: Designations block, UNS line
    - system: UNS
      code: R50550
      note: CP grade 3
      source: ati-cp3
      where: Designations block, title line ATI 55 CP Grade 3
    - system: UNS
      code: R50700
      note: CP grade 4
      source: ati-cp4
      where: Designations block, UNS line
    - system: ASTM
      code: B265
      source: ati-cp1
      where: Designations block, Bar and Billet specifications line
tags:
  environments: []
  stresses: []
  applications:
    - propulsion-and-tanks
    - structures
properties:
  - benchmark: density
    label: Density, CP grade 1
    value: 4.51
    unit: g/cm3
    scope: material
    conditions:
      grade: CP grade 1 (UNS R50250)
      form: all forms as printed
      unit_in_source: 0.163 lb/in3
    method: Value printed in a manufacturer product page (ATI)
    status: ground
    source: ati-cp1
    where: Density row, all forms
  - benchmark: density
    label: Density, CP grade 2 (bar and billet)
    value: 4.51
    unit: g/cm3
    scope: material
    conditions:
      grade: CP grade 2 (UNS R50400)
      form: bar and billet
      unit_in_source: 0.163 lb/in3
    method: Value printed in a manufacturer product page (ATI)
    status: ground
    note: The same ATI page prints 4.52 g/cm3 for plate, sheet and strip of grade 2.
    source: ati-cp2
    where: Density row, Bar and Billet section
  - benchmark: density
    label: Density, CP grade 3
    value: 4.51
    unit: g/cm3
    scope: material
    conditions:
      grade: CP grade 3 (UNS R50550)
      form: all forms as printed
      unit_in_source: 0.163 lb/in3
    method: Value printed in a manufacturer product page (ATI)
    status: ground
    source: ati-cp3
    where: Density row, Bar and Billet and Plate, Sheet and Strip sections
  - benchmark: density
    label: Density, CP grade 4 (bar and billet)
    value: 4.51
    unit: g/cm3
    scope: material
    conditions:
      grade: CP grade 4 (UNS R50700)
      form: bar and billet
      unit_in_source: 0.163 lb/in3
    method: Value printed in a manufacturer product page (ATI)
    status: ground
    note: The same ATI page prints 4.52 g/cm3 for plate and strip and 4.51 g/cm3 for sheet of grade 4.
    source: ati-cp4
    where: Density row, Bar and Billet section
  - benchmark: ultimate_tensile_strength
    label: Tensile strength minimum, CP grade 1
    value: 240
    bound: lower
    unit: MPa
    scope: material
    conditions:
      grade: CP grade 1 (UNS R50250)
      form: all forms as printed
      basis: minimum
      unit_in_source: 35 min ksi
    method: Minimum value printed in a manufacturer product page (ATI)
    status: ground
    source: ati-cp1
    where: Tensile Strength row, all forms, MPa column
  - benchmark: ultimate_tensile_strength
    label: Tensile strength minimum, CP grade 2
    value: 345
    bound: lower
    unit: MPa
    scope: material
    conditions:
      grade: CP grade 2 (UNS R50400)
      form: bar, billet, plate, sheet and strip (same minimum in each)
      basis: minimum
      unit_in_source: 50 min ksi
    method: Minimum value printed in a manufacturer product page (ATI)
    status: ground
    source: ati-cp2
    where: Tensile Strength row, Bar and Billet and Plate sections, MPa column
  - benchmark: ultimate_tensile_strength
    label: Tensile strength minimum, CP grade 3
    value: 450
    bound: lower
    unit: MPa
    scope: material
    conditions:
      grade: CP grade 3 (UNS R50550)
      form: bar, billet, plate, sheet and strip (same minimum in each)
      basis: minimum
      unit_in_source: 65 min ksi
    method: Minimum value printed in a manufacturer product page (ATI)
    status: ground
    source: ati-cp3
    where: Tensile Strength row, MPa column
  - benchmark: ultimate_tensile_strength
    label: Tensile strength minimum, CP grade 4
    value: 550
    bound: lower
    unit: MPa
    scope: material
    conditions:
      grade: CP grade 4 (UNS R50700)
      form: bar, billet, plate, sheet and strip (same minimum in each)
      basis: minimum
      unit_in_source: 80 min ksi
    method: Minimum value printed in a manufacturer product page (ATI)
    status: ground
    source: ati-cp4
    where: Tensile Strength row, MPa column
  - benchmark: yield_strength
    label: Yield strength Rp0.2 minimum, CP grade 1
    value: 138
    bound: lower
    unit: MPa
    scope: material
    conditions:
      grade: CP grade 1 (UNS R50250)
      form: bar, billet and plate
      basis: minimum
      unit_in_source: 20 min ksi
    method: Minimum value printed in a manufacturer product page (ATI)
    status: ground
    note: The same ATI page prints 138 min to 310 max MPa for sheet and strip of grade 1.
    source: ati-cp1
    where: Yield Strength row, Bar, Billet, Plate section, MPa column
  - benchmark: yield_strength
    label: Yield strength minimum, CP grade 2 (bar and billet)
    value: 275
    bound: lower
    unit: MPa
    scope: material
    conditions:
      grade: CP grade 2 (UNS R50400)
      form: bar and billet
      basis: minimum
      unit_in_source: 40 min ksi
    method: Minimum value printed in a manufacturer product page (ATI)
    status: ground
    note: The same ATI page prints 275 min to 450 max MPa for plate, sheet and strip of grade 2.
    source: ati-cp2
    where: Yield Strength row, Bar and Billet section, MPa column
  - benchmark: yield_strength
    label: Yield strength minimum, CP grade 3 (bar and billet)
    value: 380
    bound: lower
    unit: MPa
    scope: material
    conditions:
      grade: CP grade 3 (UNS R50550)
      form: bar and billet
      basis: minimum
      unit_in_source: 55 min ksi
    method: Minimum value printed in a manufacturer product page (ATI)
    status: ground
    note: The same ATI page prints 380 min to 550 max MPa for plate, sheet and strip of grade 3.
    source: ati-cp3
    where: Yield Strength row, Bar and Billet section, MPa column
  - benchmark: yield_strength
    label: Yield strength minimum, CP grade 4 (bar and billet)
    value: 483
    bound: lower
    unit: MPa
    scope: material
    conditions:
      grade: CP grade 4 (UNS R50700)
      form: bar and billet
      basis: minimum
      unit_in_source: 70 min ksi
    method: Minimum value printed in a manufacturer product page (ATI)
    status: ground
    note: The same ATI page prints 483 min to 655 max MPa for plate and strip of grade 4.
    source: ati-cp4
    where: Yield Strength row, Bar and Billet section, MPa column
  - benchmark: elongation
    label: Elongation minimum, CP grade 1
    value: 24
    bound: lower
    unit: '%'
    scope: material
    conditions:
      grade: CP grade 1 (UNS R50250)
      form: all forms as printed
      basis: minimum
    method: Minimum value printed in a manufacturer product page (ATI)
    status: ground
    source: ati-cp1
    where: Elongation row, all forms
  - benchmark: elongation
    label: Elongation minimum, CP grade 2
    value: 20
    bound: lower
    unit: '%'
    scope: material
    conditions:
      grade: CP grade 2 (UNS R50400)
      form: bar, billet, plate, sheet and strip
      basis: minimum
    method: Minimum value printed in a manufacturer product page (ATI)
    status: ground
    source: ati-cp2
    where: Elongation row, Bar and Billet and Plate, Sheet and Strip sections
  - benchmark: elongation
    label: Elongation minimum, CP grade 3
    value: 18
    bound: lower
    unit: '%'
    scope: material
    conditions:
      grade: CP grade 3 (UNS R50550)
      form: bar, billet, plate, sheet and strip
      basis: minimum
    method: Minimum value printed in a manufacturer product page (ATI)
    status: ground
    source: ati-cp3
    where: Elongation row, Bar and Plate sections
  - benchmark: elongation
    label: Elongation minimum, CP grade 4
    value: 15
    bound: lower
    unit: '%'
    scope: material
    conditions:
      grade: CP grade 4 (UNS R50700)
      form: bar, billet, plate and strip
      basis: minimum
    method: Minimum value printed in a manufacturer product page (ATI)
    status: ground
    source: ati-cp4
    where: Elongation row, Bar and Billet and Plate, Sheet and Strip sections
  - benchmark: density
    label: Density, titanium element
    value: 4.507
    unit: g/cm3
    scope: material
    conditions:
      form: pure element titanium
      temperature: not stated on the page
    method: Value printed on a periodic-table data page for the element
    status: ground
    source: periodictable-ti
    where: Overview and Bulk physical properties sections
  - benchmark: melting_point
    label: Melting point, titanium element
    value: 1668
    unit: °C
    scope: material
    conditions:
      form: pure element titanium
      pressure: not stated on the page
    method: Value printed on a periodic-table data page for the element
    status: ground
    note: The ATI pages for the CP grades print no melting point.
    source: periodictable-ti
    where: Overview and Thermal properties sections
  - benchmark: thermal_conductivity
    label: Thermal conductivity, titanium element
    value: 21.9
    unit: W/(m·K)
    scope: material
    conditions:
      form: pure element titanium
      temperature: not stated on the page
      unit_in_source: W m-1 K-1
    method: Value printed on a WebElements physical properties page
    status: ground
    note: The periodic-table data page prints 22 W/(m K) for the same property, which rounds this figure.
    source: webelements-ti
    where: Heat and conduction section, Thermal conductivity
  - benchmark: elastic_modulus
    label: Young's modulus, titanium element
    value: 116
    unit: GPa
    scope: material
    conditions:
      form: pure element titanium
      temperature: not stated on the page
    method: Value printed on a WebElements physical properties page
    status: ground
    source: webelements-ti
    where: Elastic properties section, Young's modulus
  - benchmark: bulk_modulus
    label: Bulk modulus, titanium element
    value: 110
    unit: GPa
    scope: material
    conditions:
      form: pure element titanium
      temperature: not stated on the page
    method: Value printed on a WebElements physical properties page
    status: ground
    source: webelements-ti
    where: Elastic properties section, Bulk modulus
  - benchmark: shear_modulus
    label: Shear (rigidity) modulus, titanium element
    value: 44
    unit: GPa
    scope: material
    conditions:
      form: pure element titanium
      temperature: not stated on the page
    method: Value printed on a WebElements physical properties page, named rigidity modulus
    status: ground
    source: webelements-ti
    where: Elastic properties section, Rigidity modulus
  - benchmark: poissons_ratio
    label: Poisson's ratio, titanium element
    value: 0.32
    unit: '-'
    scope: material
    conditions:
      form: pure element titanium
      unit_in_source: no units printed
    method: Value printed on a WebElements physical properties page
    status: ground
    source: webelements-ti
    where: Elastic properties section, Poisson's ratio
  - benchmark: specific_heat
    label: Specific heat capacity, titanium element
    value: 520
    unit: J/(kg·K)
    scope: material
    conditions:
      form: solid phase, pure element titanium
    method: Value printed on a periodic-table data page for the element
    status: ground
    source: periodictable-ti
    where: Thermal properties section, Specific heat
corrosion:
  - environment: Oxidizing acids and air (passive oxide film)
    headline: A thin passive oxide layer protects titanium against oxidizing acids.
    effect: Wikipedia describes a thin, non-porous passivation layer that protects the bulk metal from further oxidation or corrosion, and says this layer gives titanium excellent resistance to corrosion against oxidizing acids. The page gives no rate.
    rating: low
    conditions:
      basis: qualitative statement in an encyclopedia article, no test conditions printed
    source: wikipedia-ti
    where: Passivation and corrosion-resistance paragraph
risks:
  hazards:
    - text: 'PubChem''s aggregate of ECHA C&L Inventory notifications for titanium: 606 of 808 company reports say the substance does not meet GHS hazard criteria, and 202 of 808 reports give hazard statement codes. The signal word given is Danger. The record says the classification may vary with impurities, additives and other factors.'
      ghs:
        - H228
        - H250
        - H251
      source: pubchem-ti
      where: GHS Classification section of the PubChem record for titanium, CID 23963
  failure_risks:
    - mode: Ignition and burning in oxygen-enriched gas
      trigger: Rods of CP grade 2 ignited at the bottom and burned upward in 70 % O2 balance N2 and in 99.5+% O2 at several pressures (NASA White Sands test)
      consequence: The burning rate increased as rod diameter decreased, and increased with test gas pressure and oxygen concentration. The authors ran this test to support a failure analysis.
      severity: high
      source: nasa-wstf-ti-flam
      where: Abstract and Background; Test Samples section (CP titanium Grade 2, UNS R50400)
    - mode: Oxygen and nitrogen change strength and ductility
      trigger: Interstitial oxygen and nitrogen above the grade's composition limits (ATI tables)
      consequence: The paper says oxygen and nitrogen exert a great extent of influence on mechanical properties, while iron and carbon have a lesser impact.
      severity: moderate
      source: redalyc-cbers
      where: Introduction, paragraph on commercially pure titanium composition
  side_effects: []
  handling:
    - text: Specify the grade and its composition limits, because oxygen and nitrogen exert a great extent of influence on mechanical properties (Orlowski de Garcia et al.).
      source: redalyc-cbers
      where: Introduction, paragraph on commercially pure titanium composition
    - text: Keep titanium away from oxygen-enriched gas and ignition sources. The NASA White Sands paper states that titanium and its alloys are easily ignited and burn vigorously in oxygen-enriched atmospheres.
      source: nasa-wstf-ti-flam
      where: Background section
    - text: For welded propulsion lines, the CBERS team worked in a clean room with controlled humidity, temperature and particulates (Orlowski de Garcia et al.).
      source: redalyc-cbers
      where: Materials and Methods, first paragraphs
  mitigations: []
uses:
  - application: propulsion-and-tanks
    device: Propulsion distribution lines (tubing between components)
    example: Grade 2 commercially pure titanium tubing was specified as the distribution lines that interconnect the components of the China-Brazil CBERS satellite propulsion system, which includes four hydrazine fuel tanks, thrusters and valves.
    source: redalyc-cbers
    where: Introduction, first two paragraphs
  - application: structures
    device: Titanium metal parts for aerospace (all titanium metal, not CP grades alone)
    example: The USGS says the majority of titanium metal was used in aerospace applications in 2025, although detailed consumption data were withheld.
    source: usgs-mcs2026-titanium
    where: Domestic Production and Use paragraph
supply:
  - subject: Titanium sponge metal (feedstock for mill products, including CP grades)
    abundance: Titanium is the ninth-most abundant element in Earth's crust, at 0.63 % by mass (Wikipedia).
    producers:
      - country: China
        share_percent: 70.3
        year: 2025
      - country: Japan
        share_percent: 14.3
        year: 2025
      - country: Russia
        share_percent: 6.8
        year: 2025
      - country: Kazakhstan
        share_percent: 4.3
        year: 2025
      - country: Saudi Arabia
        share_percent: 3.2
        year: 2025
    critical_lists: []
    recycling: 'USGS: U.S. imports of titanium scrap were estimated at 32,000 tons in 2025, and consumption data for titanium scrap in the titanium metal industry were withheld. A company in Virginia began titanium powder production from scrap in late 2024.'
    substitutes:
      - 'USGS: aluminum, nickel, specialty steels and zirconium alloys may be substituted for titanium where corrosion resistance is required.'
    source: usgs-mcs2026-titanium
    where: 'World Sponge Metal Production table, 2025e column (metric tons: China 260,000; Japan 53,000; Russia 25,000; Kazakhstan 16,000; Saudi Arabia 12,000; world total 370,000). Shares are country value divided by 370,000, calculated by Space Mushroom. Also the Recycling, Substitutes and Events, Trends, and Issues sections.'
  - subject: Titanium ore feedstock (rutile or ilmenite for the Kroll process)
    producers: []
    critical_lists: []
    substitutes: []
    source: wikipedia-ti
    where: Production paragraph (Kroll process) and its feedstock sentence
documents:
  - title: ATI 30, CP Grade 1 Titanium product page
    type: datasheet
    url: https://www.atimaterials.com/Products/ati-cp1
  - title: ATI CP Grade 2 Titanium product page
    type: datasheet
    url: https://www.atimaterials.com/Products/ati-cp2
  - title: ATI 55, CP Grade 3 Titanium product page
    type: datasheet
    url: https://www.atimaterials.com/Products/ati-cp3
  - title: ATI 70, CP Grade 4 Titanium product page
    type: datasheet
    url: https://www.atimaterials.com/Products/ati-cp4
  - title: 'WebElements: Titanium physical properties'
    type: database
    url: https://www.webelements.com/titanium/physics.html
  - title: 'Periodic Table: Titanium element data'
    type: database
    url: https://periodictable.com/Elements/022/data.html
  - title: 'USGS Mineral Commodity Summaries 2026: Titanium and Titanium Dioxide'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-titanium.pdf
    year: 2026
  - title: PubChem compound record for titanium, CID 23963 (GHS classification)
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/23963
  - title: 'Wikipedia: Titanium'
    type: database
    url: https://en.wikipedia.org/wiki/Titanium
  - title: Orlowski de Garcia et al., Advances of orbital gas tungsten arc welding for Brazilian space applications, Journal of Aerospace Technology and Management, 2010
    type: paper
    url: https://www.redalyc.org/pdf/3094/309426553009.pdf
    year: 2010
  - title: Stoltzfus, Jeffers and Gallus, Burning of CP Titanium (Grade 2) in Oxygen-Enriched Atmospheres, ASTM International, 2012
    type: paper
    url: https://ntrs.nasa.gov/citations/20120002982
    year: 2012
gaps:
  - Melting point, thermal conductivity and elastic modulus for each CP grade were not printed on the ATI pages. The values recorded are for the pure element, from WebElements and periodictable.com.
  - Coefficient of thermal expansion and electrical resistivity are printed in exponent notation on WebElements and periodictable.com, so they are left out under the exponent rule.
  - Hardness, fatigue strength, fracture toughness and creep for the CP grades were not read in this run.
  - Seawater and chloride corrosion rates for the CP grades were not read in this run. The titanium grade 2 profile covers the grade 2 datasheets for that environment.
  - The titanium critical-mineral list status was not in the USGS 2026 text we read, so critical_lists is empty.
  - PubChem's hazard percentages were not captured. The counts of 606 of 808 and 202 of 808 reports are recorded instead.
  - Radiation, atomic oxygen and vacuum outgassing data for titanium were not looked up.
  - Recycling rates for titanium scrap were not found. USGS withheld the consumption data.
  - Space uses of CP grades beyond the CBERS propulsion distribution lines were not found. The USGS use text covers titanium metal in general, not CP grades alone.
  - Composition limits are recorded in identity.formula and the recipe, not as property rows.
sources:
  ati-cp1:
    title: ATI 30, CP Grade 1 Titanium product page (ATI Materials)
    url: https://www.atimaterials.com/Products/ati-cp1
    kind: datasheet
  ati-cp2:
    title: ATI CP Grade 2 Titanium product page (ATI Materials)
    url: https://www.atimaterials.com/Products/ati-cp2
    kind: datasheet
  ati-cp3:
    title: ATI 55, CP Grade 3 Titanium product page (ATI Materials)
    url: https://www.atimaterials.com/Products/ati-cp3
    kind: datasheet
  ati-cp4:
    title: ATI 70, CP Grade 4 Titanium product page (ATI Materials)
    url: https://www.atimaterials.com/Products/ati-cp4
    kind: datasheet
  webelements-ti:
    title: 'WebElements: Titanium physical properties'
    url: https://www.webelements.com/titanium/physics.html
    kind: database
  periodictable-ti:
    title: 'Periodic Table: Titanium element data'
    url: https://periodictable.com/Elements/022/data.html
    kind: database
  usgs-mcs2026-titanium:
    title: 'USGS Mineral Commodity Summaries 2026: Titanium and Titanium Dioxide'
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-titanium.pdf
    year: 2026
    kind: report
  pubchem-ti:
    title: PubChem compound record for titanium, CID 23963
    url: https://pubchem.ncbi.nlm.nih.gov/compound/23963
    kind: database
  wikipedia-ti:
    title: 'Wikipedia: Titanium'
    url: https://en.wikipedia.org/wiki/Titanium
    kind: web
    license: CC BY-SA 4.0 (cited, not reproduced)
  redalyc-cbers:
    title: Orlowski de Garcia et al., Advances of orbital gas tungsten arc welding for Brazilian space applications - experimental setup, Journal of Aerospace Technology and Management 2(2), 2010
    url: https://www.redalyc.org/pdf/3094/309426553009.pdf
    year: 2010
    kind: paper
  nasa-wstf-ti-flam:
    title: Stoltzfus, Jeffers and Gallus, Burning of CP Titanium (Grade 2) in Oxygen-Enriched Atmospheres, Journal of ASTM International (NASA JSC-CN-25709)
    url: https://ntrs.nasa.gov/citations/20120002982
    year: 2012
    kind: paper
license: CC-BY-4.0
updated: '2026-11-01'
review:
  status: draft
  method: assistant
  checked_values: 24
  unreachable: 0
  caveats: 0
  note: Written by an AI assistant on 2026-11-01 from the cited pages. Values were copied from the fetched pages; see gaps for what was not found.
story:
  recipe:
    line: Commercially pure titanium is the element titanium, with small, limited amounts of oxygen, iron, carbon, nitrogen and hydrogen. Titanium metal is made by the Kroll process, which reduces titanium tetrachloride with magnesium (Wikipedia).
    parts:
      - name: Titanium
        symbol: Ti
        role: Main metal, which makes up the balance of each grade
        share_note: balance
        source: ati-cp1
        where: Composition table, Ti row
      - name: Oxygen
        symbol: O
        role: Interstitial impurity; the paper says oxygen and nitrogen have a great effect on mechanical properties
        share_note: maximum, by grade (see identity formula)
        source: ati-cp4
        where: Composition table, O row
      - name: Iron
        symbol: Fe
        role: Impurity with a lesser effect on mechanical properties than oxygen
        share_note: maximum, by grade (see identity formula)
        source: ati-cp1
        where: Composition table, Fe row
      - name: Carbon
        symbol: C
        role: Interstitial impurity; the composition table prints 0.08 max in all four grades
        share_note: maximum
        source: ati-cp1
        where: Composition table, C row
      - name: Nitrogen
        symbol: 'N'
        role: Interstitial impurity, limited by grade and form
        share_note: maximum, by grade (see identity formula)
        source: ati-cp3
        where: Composition table, N row
      - name: Hydrogen
        symbol: H
        role: Interstitial impurity
        share_note: maximum 0.015 in all four grades
        source: ati-cp1
        where: Composition table, H row
  risk_groups:
    - title: For people
      lead: The GHS record for elemental titanium is mostly 'not classified', but some company notifications carry hazard codes.
      points:
        - label: Classification
          line: PubChem records 606 of 808 company reports as not meeting GHS hazard criteria, and 202 of 808 reports with hazard statement codes (ECHA C&L Inventory aggregate).
        - label: Hazard codes
          line: The codes given are H228 flammable solid, H250 catches fire spontaneously if exposed to air, and H251 self-heating, with signal word Danger.
        - label: Impurities
          line: PubChem says the classification may vary with impurities, additives and other factors.
      level: 2
      verdict: Mostly not classified
    - title: Ignition and burning
      lead: NASA's White Sands test facility measured how CP grade 2 rods burn in oxygen-enriched gas (Stoltzfus et al., 2012).
      points:
        - label: Test gas
          line: Rods were ignited at the bottom and burned upward in 70 % O2 balance N2 and in 99.5+% O2 at several pressures.
        - label: Diameter
          line: The burning rate increased as diameter decreased, and it increased with test gas pressure and oxygen concentration.
      level: 3
      verdict: Burns in oxygen-enriched gas
  why: 'Commercially pure (CP) titanium is unalloyed titanium sold as four ASTM grades, numbered 1 to 4. The grades differ mainly in strength: ATI prints a minimum yield strength of 138 MPa for grade 1 bar and billet, against 483 MPa for grade 4. CP titanium suits corrosion-resistant parts where strength is not the top requirement, and grade 2 tubing was used for the propulsion distribution lines of the China-Brazil CBERS satellite.'
  uses:
    - where: Satellite propulsion plumbing
      line: Grade 2 commercially pure titanium tubing was specified as the distribution lines that connect the components of the CBERS satellite propulsion system (Orlowski de Garcia et al., 2010).
    - where: Aerospace
      line: The USGS says the majority of titanium metal in 2025 was used in aerospace applications, with the rest going to armor, chemical processing, marine hardware, medical implants and power generation. This covers titanium metal in general, not the CP grades alone.
  can_do:
    - label: Strength
      line: Grade 1 bar and billet have a minimum yield strength of 138 MPa, and grade 4 bar and billet have 483 MPa minimum (ATI).
    - label: Density
      line: ATI prints 4.51 g/cm3 for each CP grade; the pure element is printed at 4.507 g/cm3 (periodictable.com).
    - label: Heat
      line: The pure element melts at 1668 °C (periodictable.com). The ATI pages print no melting point for the CP grades.
    - label: Ductility
      line: The minimum elongation falls from 24 % in grade 1 to 15 % in grade 4 (ATI).
  compare: 'Across the four grades, a higher grade number buys strength at the cost of ductility: grade 1 has a minimum tensile strength of 240 MPa and 24 % elongation, while grade 4 has 550 MPa and 15 % (ATI). The Brazilian satellite welding paper says CP titanium welds well because it has low thermal conductivity and low linear thermal expansion. The record holds no comparison with other metals, so none is made here.'
  compare_rows:
    - label: Yield strength, minimum, bar and billet
      benchmark: yield_strength
    - label: Tensile strength, minimum
      benchmark: ultimate_tensile_strength
    - label: Density
      benchmark: density
  handling:
    - Oxygen and nitrogen strongly affect the properties, so buy to the grade's composition limits (Orlowski de Garcia et al.).
    - Keep titanium away from oxygen-enriched gas and ignition sources. The NASA paper says titanium and its alloys are easily ignited and burn vigorously in oxygen-enriched atmospheres.
    - For welded propulsion lines, the CBERS team worked in a clean room with controlled humidity, temperature and particulates.
  good_for:
    - Corrosion-resistant tubing and plumbing where strength is not the highest requirement. The paper says CP grades serve applications where corrosion resistance and high ductility matter more than mechanical resistance.
    - Welded parts. The paper cites good weldability from low thermal conductivity and low linear thermal expansion.
  watch_out:
    - 'Strength climbs with the grade number: 138 MPa minimum yield for grade 1, 483 MPa for grade 4 (ATI).'
    - Titanium burns in oxygen-enriched gas. Ignition is the failure mode to design against (NASA White Sands).
    - Oxygen and nitrogen have a great influence on mechanical properties, so the composition limits matter (Orlowski de Garcia et al.).
  verdict: Commercially pure titanium is the choice when corrosion resistance and ductility matter more than strength. Grade 1 is the most ductile and grade 4 the strongest, as ATI's minimum values show.