spore: profile
id: brass-c360
spore_version: 0.2
family: copper-alloys
name: Free-cutting brass C36000
abbreviation: C360
role: free-cutting machining alloy
category: metals
type: copper-alloys
summary: |
  Free-cutting brass C36000 (UNS C36000, CuZn36Pb3) is a copper-zinc alloy with 2.5 to 3.0 % lead, made for high-speed screw-machine work. Its machinability is rated 100 on the supplier scale. Its density is 8.5 g/cm3, its electrical conductivity is 26 %IACS and its thermal conductivity is 116 W/(m·K) at 20 °C. Strength depends on temper: round rod has a minimum tensile strength of 330 MPa annealed (O60), 390 MPa half hard (H02) and 480 MPa hard (H04), and its elongation falls from 15 % to 4 % across those tempers. The alloy dezincifies in water and can crack under tensile stress in ammonia, and its lead content keeps it out of California's lead-free plumbing brass (limit 0.25 % lead). For the pure metal see the [copper profile](/profiles/copper/).
best_for: High-volume machined parts such as screw-machine products, fasteners and valve components, where machinability rated 100 matters most
weakest_at: Corrosion in water (dezincification, about 35 % zinc) and in ammonia (season cracking), plus its 2.5 to 3.0 % lead content
identity:
  formula: 'CuZn36Pb3, UNS C36000: copper 60.0 to 63.0 wt%, lead 2.5 to 3.0 wt%, iron 0.35 wt% maximum, zinc remainder'
  source: aviva-c36000
  where: Chemical Composition limits on the Aviva product page (Cu 60-63, Pb 2.5-3.0, Fe 0.35 max, Zn rem); the same limits appear on the Fisk MA36B page. Wikipedia's C360 row gives lead 2.5 to 3.7 wt%.
  designations:
    - system: UNS
      code: C36000
      source: fisk-ma36b
      where: 'Page title: C36000 Free-Cutting Brass (CuZn36Pb3)'
    - system: CDA
      code: C360
      source: natbronze-c36000
      where: 'Page title: C36000 Free Cutting Brass Bar / C360 Brass / Free Machining Brass'
    - system: EN name
      code: CW603N
      source: wieland-brass-alloys
      where: Brass alloys table, row Z23 (EN designation CuZn36Pb3), EN No. column
    - system: EN name
      code: CuZn36Pb3
      source: fisk-ma36b
      where: 'Page title: C36000 Free-Cutting Brass (CuZn36Pb3)'
    - system: BS
      code: CZ124
      note: nearest equivalent
      source: aalco-copper-brass-bronze
      where: Wrought copper-zinc-lead alloys table, row CuZn36Pb3 (CW603N), Old BS Equivalent column; BS to EN conversion table, row CuZn36Pb3
    - system: ASTM
      code: B16
      source: fisk-ma36b
      where: Specifications line (ASTM B16, EN 12164, EN 12166); product form not stated
    - system: Trade name
      code: Free Machining Brass
      source: natbronze-c36000
      where: 'Page title: C36000 Free Cutting Brass Bar / C360 Brass / Free Machining Brass'
    - system: Trade name
      code: Free Cutting Brass
      source: fisk-ma36b
      where: 'Page title: C36000 Free-Cutting Brass (CuZn36Pb3)'
tags:
  environments: []
  stresses: []
  applications:
    - mechanisms
    - habitats-and-suits
properties:
  - benchmark: density
    label: Density, C36000 (Fisk MA36B)
    value: 8.5
    unit: g/cm3
    scope: material
    conditions:
      grade: C36000 (Fisk MA36B)
      temper: not stated; one value printed for the alloy
      temperature: not stated
      unit_in_source: 0.307 lb/in3 (English column)
    method: Value printed in the metric column of a supplier's physical properties table
    status: ground
    source: fisk-ma36b
    where: Physical Properties table, Density row, metric column
  - benchmark: melting_point
    label: Solidus, C36000 (Fisk MA36B)
    value: 954
    unit: °C
    scope: material
    conditions:
      grade: C36000 (Fisk MA36B)
      unit_in_source: 1,750 °F
      pressure: not stated
    method: Value printed in the metric column of a supplier's physical properties table
    status: ground
    source: fisk-ma36b
    where: Physical Properties table, Melting Point (Solidus) row, metric column
  - benchmark: melting_point
    label: Liquidus, C36000 (Fisk MA36B)
    value: 1049
    unit: °C
    scope: material
    conditions:
      grade: C36000 (Fisk MA36B)
      unit_in_source: 1,920 °F
      pressure: not stated
    method: Value printed in the metric column of a supplier's physical properties table
    status: ground
    source: fisk-ma36b
    where: Physical Properties table, Melting Point (Liquidus) row, metric column
  - benchmark: thermal_conductivity
    label: Thermal conductivity at 20 °C, C36000 (Fisk MA36B)
    value: 116
    unit: W/(m·K)
    scope: material
    conditions:
      grade: C36000 (Fisk MA36B)
      temperature: 20 °C
      temper: not stated; one value printed for the alloy
    method: Value printed in the metric column of a supplier's physical properties table
    status: ground
    source: fisk-ma36b
    where: Physical Properties table, Thermal Conductivity row, metric column
  - benchmark: cte
    label: Coefficient of thermal expansion, 20 to 300 °C (Fisk MA36B)
    value: 20.5
    unit: ppm/K
    scope: material
    conditions:
      grade: C36000 (Fisk MA36B)
      temperature: 20 to 300 °C
      temper: not stated
      unit_in_source: 20.5 per °C (20-300 °C)
    method: Printed as per °C; this is 10^-6 per kelvin, the same unit as ppm/K, so the number is copied without conversion
    status: ground
    source: fisk-ma36b
    where: Physical Properties table, Coefficient of Thermal Expansion row, metric column
  - benchmark: electrical_conductivity
    label: Electrical conductivity, annealed C36000 (Fisk MA36B)
    value: 26
    unit: '%IACS'
    scope: material
    conditions:
      grade: C36000 (Fisk MA36B)
      temper: annealed (O60)
      temperature: 68 °F (20 °C)
      unit_in_source: 26% IACS @ 68 °F (English column)
    method: Value printed in the English column of a supplier's physical properties table; the metric column for the same row (0.15 MS·cm) does not convert to 26 %IACS and is not used
    status: ground
    source: fisk-ma36b
    where: Physical Properties table, Electrical Conductivity (Annealed) row
  - benchmark: electrical_resistivity
    label: Electrical resistivity, annealed C36000 (Fisk MA36B)
    value: 6.63
    unit: µΩ·cm
    scope: material
    conditions:
      grade: C36000 (Fisk MA36B)
      temper: annealed (O60)
      temperature: 20 °C
      unit_in_source: 39.9 Ω·cir-mil/ft @ 68 °F (English column)
    method: Value printed in the metric column of a supplier's physical properties table
    status: ground
    source: fisk-ma36b
    where: Physical Properties table, Electrical Resistivity (Annealed) row, metric column
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, annealed O60 round rod (minimum)
    value: 330
    bound: lower
    unit: MPa
    scope: material
    conditions:
      grade: C36000 (Fisk MA36B)
      temper: O60, annealed (soft)
      product_form: round rod, mill limits 1.59 to 6.35 mm
      measure: minimum
      unit_in_source: 48.0 ksi (English block)
    method: Minimum value printed in a supplier's pretempered round rod table, metric block
    status: ground
    source: fisk-ma36b
    where: Round Rod - Pretempered table, metric block, row Annealed O60, column Tensile strength (MPa) Min
  - benchmark: yield_strength
    label: Yield strength, annealed O60 round rod (minimum, 0.5 % extension under load)
    value: 130
    bound: lower
    unit: MPa
    scope: material
    conditions:
      grade: C36000 (Fisk MA36B)
      temper: O60, annealed (soft)
      product_form: round rod, mill limits 1.59 to 6.35 mm
      measure: minimum, 0.5 % extension under load
      unit_in_source: 20.0 ksi (English block)
    method: Minimum value printed in a supplier's pretempered round rod table; the yield definition is 0.5 % extension under load, not the 0.2 % offset
    status: ground
    source: fisk-ma36b
    where: Round Rod - Pretempered table, metric block, row Annealed O60, column Yield strength 0.5% EUL (MPa) Min
  - benchmark: elongation
    label: Elongation, annealed O60 round rod (minimum)
    value: 15
    bound: lower
    unit: '%'
    scope: material
    conditions:
      grade: C36000 (Fisk MA36B)
      temper: O60, annealed (soft)
      product_form: round rod, mill limits 1.59 to 6.35 mm
      gauge_length: 1 in (1 GL column header)
    method: Value printed in a supplier's pretempered round rod table, metric block
    status: ground
    source: fisk-ma36b
    where: Round Rod - Pretempered table, metric block, row Annealed O60, column Elongation (%) 1 in GL
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, half-hard H02 round rod (minimum)
    value: 390
    bound: lower
    unit: MPa
    scope: material
    conditions:
      grade: C36000 (Fisk MA36B)
      temper: H02, half hard (1/2 hard)
      product_form: round rod, mill limits 1.59 to 6.35 mm
      measure: minimum
      unit_in_source: 57.0 ksi (English block)
    method: Minimum value printed in a supplier's pretempered round rod table, metric block
    status: ground
    source: fisk-ma36b
    where: Round Rod - Pretempered table, metric block, row H02, column Tensile strength (MPa) Min
  - benchmark: yield_strength
    label: Yield strength, half-hard H02 round rod (minimum, 0.5 % extension under load)
    value: 170
    bound: lower
    unit: MPa
    scope: material
    conditions:
      grade: C36000 (Fisk MA36B)
      temper: H02, half hard (1/2 hard)
      product_form: round rod, mill limits 1.59 to 6.35 mm
      measure: minimum, 0.5 % extension under load
      unit_in_source: 25.0 ksi (English block)
    method: Minimum value printed in a supplier's pretempered round rod table; the yield definition is 0.5 % extension under load
    status: ground
    source: fisk-ma36b
    where: Round Rod - Pretempered table, metric block, row H02, column Yield strength 0.5% EUL (MPa) Min
  - benchmark: elongation
    label: Elongation, half-hard H02 round rod (minimum)
    value: 7
    bound: lower
    unit: '%'
    scope: material
    conditions:
      grade: C36000 (Fisk MA36B)
      temper: H02, half hard (1/2 hard)
      product_form: round rod, mill limits 1.59 to 6.35 mm
      gauge_length: 1 in (1 GL column header)
    method: Value printed in a supplier's pretempered round rod table, metric block
    status: ground
    source: fisk-ma36b
    where: Round Rod - Pretempered table, metric block, row H02, column Elongation (%) 1 in GL
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, hard H04 round rod (minimum)
    value: 480
    bound: lower
    unit: MPa
    scope: material
    conditions:
      grade: C36000 (Fisk MA36B)
      temper: H04, hard
      product_form: round rod, mill limits 4.77 to 6.35 mm
      measure: minimum
      unit_in_source: 70.0 ksi (English block)
    method: Minimum value printed in a supplier's pretempered round rod table, metric block
    status: ground
    source: fisk-ma36b
    where: Round Rod - Pretempered table, metric block, row Hard H04, column Tensile strength (MPa) Min
  - benchmark: yield_strength
    label: Yield strength, hard H04 round rod (minimum, 0.5 % extension under load)
    value: 240
    bound: lower
    unit: MPa
    scope: material
    conditions:
      grade: C36000 (Fisk MA36B)
      temper: H04, hard
      product_form: round rod, mill limits 4.77 to 6.35 mm
      measure: minimum, 0.5 % extension under load
      unit_in_source: 35.0 ksi (English block)
    method: Minimum value printed in a supplier's pretempered round rod table; the yield definition is 0.5 % extension under load
    status: ground
    source: fisk-ma36b
    where: Round Rod - Pretempered table, metric block, row Hard H04, column Yield strength 0.5% EUL (MPa) Min
  - benchmark: elongation
    label: Elongation, hard H04 round rod (minimum)
    value: 4
    bound: lower
    unit: '%'
    scope: material
    conditions:
      grade: C36000 (Fisk MA36B)
      temper: H04, hard
      product_form: round rod, mill limits 4.77 to 6.35 mm
      gauge_length: 1 in (1 GL column header)
    method: Value printed in a supplier's pretempered round rod table, metric block
    status: ground
    source: fisk-ma36b
    where: Round Rod - Pretempered table, metric block, row Hard H04, column Elongation (%) 1 in GL
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, half-hard H02 bar, 12.7 mm and under (minimum)
    value: 395
    bound: lower
    unit: MPa
    scope: material
    conditions:
      grade: C36000
      temper: H02, 1/2 hard
      product_form: bar, diameter or distance between parallel surfaces 12.7 mm and under
      measure: minimum
    method: Minimum value printed in a manufacturer's comparison table (Model 3 against C36000), C36000 column
    status: ground
    source: aviva-c36000
    where: Model 3 Compared to C36000 table, row H02 1/2 Hard, size 1/2 in (12.7 mm and under), column Tensile Strength min C36000
  - benchmark: yield_strength
    label: Yield strength, half-hard H02 bar, 12.7 mm and under (minimum, 0.5 % extension under load)
    value: 170
    bound: lower
    unit: MPa
    scope: material
    conditions:
      grade: C36000
      temper: H02, 1/2 hard
      product_form: bar, diameter or distance between parallel surfaces 12.7 mm and under
      measure: minimum, 0.5 % extension under load
    method: Minimum value printed in a manufacturer's comparison table, C36000 column; the yield definition is 0.5 % extension under load
    status: ground
    source: aviva-c36000
    where: Model 3 Compared to C36000 table, row H02 1/2 Hard, size 1/2 in and under, column Yield Strength at 0.5% Extension Under Load min C36000
  - benchmark: elongation
    label: Elongation, half-hard H02 bar, 12.7 mm and under (minimum)
    value: 7
    bound: lower
    unit: '%'
    scope: material
    conditions:
      grade: C36000
      temper: H02, 1/2 hard
      product_form: bar, 12.7 mm and under
      measure: minimum
    method: Minimum value printed in a manufacturer's comparison table, C36000 column
    status: ground
    source: aviva-c36000
    where: Model 3 Compared to C36000 table, row H02 1/2 Hard, size 1/2 in and under, column Elongation min C36000
  - benchmark: hardness_rockwell_b
    label: Hardness, half-hard H02 bar, 12.7 mm and under (range)
    value: 60
    value_high: 80
    bound: range
    unit: HRB
    scope: material
    conditions:
      grade: C36000
      temper: H02, 1/2 hard
      product_form: bar, 12.7 mm and under
    method: Range printed in a manufacturer's comparison table, C36000 column (Rockwell B scale as printed as HRB)
    status: ground
    source: aviva-c36000
    where: Model 3 Compared to C36000 table, row H02 1/2 Hard, size 1/2 in and under, column Hardness (HRB) C36000
  - benchmark: electrical_conductivity
    label: Electrical conductivity, half-hard H02 bar, 12.7 mm and under
    value: 26
    unit: '%IACS'
    scope: material
    conditions:
      grade: C36000
      temper: H02, 1/2 hard
      product_form: bar, 12.7 mm and under
    method: Value printed in a manufacturer's comparison table, C36000 column; the page prints the unit as % AICS, read here as %IACS
    status: ground
    source: aviva-c36000
    where: Model 3 Compared to C36000 table, row H02 1/2 Hard, size 1/2 in and under, column Conductivity C36000
  - benchmark: machinability_rating
    label: Machinability rating, C36000 bar (supplier scale, C36000 = 100)
    value: 100
    unit: '%'
    scope: material
    conditions:
      grade: C36000
      temper: not stated
      product_form: bar
      basis: relative index with C36000 defined as 100 %
    method: Index printed in a manufacturer's comparison table; it is a relative rating, not a measured property
    status: ground
    source: aviva-c36000
    where: Model 3 Compared to C36000 table, row H02 1/2 Hard, column Machinability C36000
  - benchmark: shear_modulus
    label: Shear modulus, C36000 (typical, Smith)
    value: 37
    unit: GPa
    scope: material
    conditions:
      grade: C36000
      temper: not stated (typical value)
      temperature: not stated
    method: Typical value printed in a supplier's datasheet, Mechanical Properties table
    status: ground
    source: smith-c36000
    where: Mechanical Properties (typical) table, Shear Modulus column
corrosion:
  - environment: Water containing chlorides, high water temperatures or soft water (dezincification)
    headline: 'Brass with more than 15 % zinc dezincifies: zinc leaves the alloy and a weak copper layer is left.'
    effect: Aviva says that in Cu-Zn alloys with more than 15 % zinc, dezincification selectively removes the zinc, leaving a relatively porous and weak layer of copper and copper oxide, and that this can create catastrophic failures. Wikipedia says dezincification-resistant brasses are used where the risk of corrosion is large, for example with high water temperatures, chlorides or soft water. C36000 has about 35 % zinc (nominal Zn 35.4 % on the National Bronze page).
    rating: moderate
    conditions:
      basis: qualitative description; no depth, rate or test time for C36000 is printed in the sources
      zinc_content: about 35 % (nominal, National Bronze)
    source: aviva-c36000
    where: Footnote to the Model 3 comparison table (asterisk note on dezincification)
  - environment: Ammonia or amine atmospheres with tensile stress (season cracking)
    headline: Brass can crack in ammonia when it is under tensile stress, and cold work leaves the stress that causes it.
    effect: The Hendrix Group says stress corrosion cracking needs a sufficiently high tensile stress together with a specific corrosive environment, which for brasses is usually ammonia or amines. Cold working such as pressing, spinning, drawing and bending leaves internal stresses that can lead to cracking unless a stress-relief heat treatment removes them. Cracks are usually localised, and may be accompanied by black staining where ammonia was involved. Wikipedia says brass is susceptible to stress corrosion cracking, especially from ammonia, and that the problem was first found in brass cartridges in the 1920s.
    rating: moderate
    conditions:
      basis: qualitative description for brasses in general; no threshold stress or time to crack for C36000 is printed
      test_example: 'Accelerated test cited on the page: axially loaded specimens in air with 10 % ammonia and 3.7 % water vapour at 35 °C (a test condition, not a service limit)'
    source: hgh-scc
    where: Sections on the environment, morphology, cold working and effect of zinc content
risks:
  hazards:
    - text: 'Lead: C36000 contains 2.5 to 3.0 wt% lead (Aviva and Fisk limits). The ATSDR ToxFAQ for lead says lead can affect almost every organ and system, that the U.S. Department of Health and Human Services considers lead and lead compounds reasonably anticipated to be human carcinogens, and that high exposure in pregnant women may cause miscarriage. No GHS code for the alloy was read.'
      ghs: []
      source: atsdr-lead
      where: ToxFAQs sections How can lead affect my health, How can lead affect children and Can lead cause cancer
    - text: California defines lead-free brass as containing no more than 0.25 % lead under AB 1953. The limit was cut from 4.0 % on 1 January 2010 (Wikipedia). C36000, at 2.5 to 3.0 % lead, is far outside that limit.
      ghs: []
      source: wiki-brass
      where: Lead content section, and the table row California lead-free brass
  failure_risks:
    - mode: Dezincification of brass in water
      trigger: Water with chlorides, high temperature or soft quality, in a brass with about 35 % zinc
      consequence: Zinc is removed, leaving a porous, weak copper and copper-oxide layer. Aviva says this can create catastrophic failures.
      severity: moderate
      source: aviva-c36000
      where: Footnote to the Model 3 comparison table
    - mode: Season cracking in ammonia
      trigger: Tensile stress from cold work (pressing, drawing, bending) or assembly, together with an ammonia or amine atmosphere
      consequence: Localised cracking, which the Hendrix Group says may be accompanied by black staining where ammonia was involved. Its crack pattern is described for simple alpha brass, not for C36000.
      severity: moderate
      source: hgh-scc
      where: Sections on morphology and stress-corrosion cracking in brass
    - mode: Brittle forming in the hard temper
      trigger: Forming or bending round rod in the hard H04 temper
      consequence: Elongation is 4.00 % minimum for H04 round rod (4.77 to 6.35 mm), against 15.0 % annealed. The source gives no forming limit.
      severity: low
      source: fisk-ma36b
      where: Round Rod - Pretempered table, metric block, rows Hard H04 and Annealed O60, column Elongation (%) 1 in GL
  side_effects:
    - text: Aviva says the U.S. plumbing industry has replaced traditional free-machining brass C36000 with lead-free alternatives since January 2010, backed by California legislation AB 1953.
      affects: Use in potable-water plumbing fittings
      source: aviva-c36000
      where: Lead-free brass section of the Aviva page
  handling:
    - text: 'Specify the temper on the drawing or order: annealed O60 rod gives 330 MPa minimum tensile and 15 % elongation; half-hard H02 gives 390 MPa and 7 %; hard H04 gives 480 MPa and 4 %.'
      source: fisk-ma36b
      where: Round Rod - Pretempered table, metric block
    - text: Stress-relieve parts after cold work (pressing, spinning, drawing, bending). The Hendrix Group says residual stresses from cold work can cause cracking unless they are removed or substantially reduced.
      source: hgh-scc
      where: Cold working section
    - text: Keep parts out of ammonia and amine atmospheres in service; the Hendrix Group names these as the usual cracking environments for brass.
      source: hgh-scc
      where: Environment section
    - text: Avoid exposure to lead. The ATSDR advises avoiding sources of lead and says a blood test is available for people who may have been exposed.
      source: atsdr-lead
      where: How can I protect my family from lead exposure; Can I get a medical test to check for lead
  mitigations:
    - text: Aviva's Model 3 alloy has less than 15 % zinc and is described as a true dezincification-resistant brass.
      source: aviva-c36000
      where: Model 3 footnote
    - text: 'Where service and process requirements allow, choose less susceptible brasses: low zinc rather than high zinc alloys, and aluminium brass rather than admiralty. The Hendrix Group says this improves resistance to stress corrosion cracking.'
      source: hgh-scc
      where: Mitigation paragraph on selecting less susceptible brasses
uses:
  - application: mechanisms
    device: Automatic screw-machine products and fasteners
    example: National Bronze lists screw machine products and fasteners as applications of C36000. Smith lists machine screw parts and high-volume parts.
    source: natbronze-c36000
    where: Applications list
  - application: habitats-and-suits
    device: Plumbing components, fittings, adaptors and fluid connectors (terrestrial use)
    example: Smith lists plumbing components, fittings and adaptors, and fluid connectors. National Bronze lists fittings and fluid connectors. No source names a space or habitat system; this application tag is our mapping.
    source: smith-c36000
    where: Key Features and Applications list
supply:
  - subject: Copper (mine production, copper content, 2025e), the main metal in brass
    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
      - country: China
        share_percent: 7.8
        year: 2025
      - country: Russia
        share_percent: 5.7
        year: 2025
    critical_lists:
      - list: U.S. Final 2025 List of Critical Minerals (copper added, per the USGS copper summary)
        listed: true
    recycling: 'USGS: brass and wire-rod mills accounted for about 80 % of the copper recovered from scrap, and copper recovered from scrap contributed about 30 % of U.S. copper supply.'
    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 the printed values 5,300, 3,200, 2,700, 1,800 and 1,300 thousand t); Critical minerals paragraph; Recycling paragraph
  - subject: Zinc (mine production, zinc content, 2025e), about 35 % of brass
    producers:
      - country: China
        share_percent: 31.5
        year: 2025
      - country: Peru
        share_percent: 11.5
        year: 2025
      - country: Australia
        share_percent: 8.5
        year: 2025
      - country: India
        share_percent: 6.7
        year: 2025
      - country: Mexico
        share_percent: 6
        year: 2025
    critical_lists: []
    recycling: 'USGS: refined zinc produced in the United States was recovered from secondary materials, including galvanizing residues and crude zinc oxide from electric arc furnace dust. U.S. net import reliance for refined zinc was 73 % of apparent consumption in 2025e.'
    substitutes:
      - 'USGS: aluminum and plastics substitute for galvanized sheet in automobiles, and many elements substitute for zinc in chemical, electronic and pigment uses. The summary names no substitute for zinc in brass.'
    source: usgs-mcs2026-zinc
    where: World Mine Production and Reserves table, 2025e (world total rounded 13,000 thousand t; shares calculated by Space Mushroom from the printed values 4,100, 1,500, 1,100, 870 and 780 thousand t); Recycling; Substitutes; Domestic Production and Use (brass and bronze as the second use of zinc)
  - subject: Lead (mine production, 2025e), about 2.5 to 3 % of brass
    producers:
      - country: China
        share_percent: 42.2
        year: 2025
      - country: Peru
        share_percent: 6.4
        year: 2025
      - country: United States
        share_percent: 6.2
        year: 2025
      - country: Russia
        share_percent: 5.8
        year: 2025
      - country: Mexico
        share_percent: 4.4
        year: 2025
    critical_lists:
      - list: U.S. Final 2025 List of Critical Minerals (lead added, per the Critical minerals paragraph of the USGS copper summary)
        listed: true
    recycling: 'USGS: nearly all secondary lead was recovered from old scrap, mostly lead-acid batteries.'
    substitutes: []
    source: usgs-mcs2026-lead
    where: World Mine Production and Reserves table, 2025e (world total rounded 4,500 thousand t; shares calculated by Space Mushroom from the printed values 1,900, 290, 280, 260 and 200 thousand t; Australia's 2025e figure did not extract cleanly from the text and is not in the list); Recycling paragraph
documents:
  - title: 'Fisk Alloy MA36B: C36000 free-cutting brass (CuZn36Pb3), physical properties, pretempered round rod table, composition'
    type: datasheet
    url: https://fiskalloy.com/product/ma36b/
  - title: 'Aviva Metals: C36000 free-machining brass, with Model 3 comparison table and dezincification note'
    type: datasheet
    url: https://avivametals.com/products/c36000-free-machining-brass-free-cutting-brass
  - title: 'Smiths Metal Centres: C36000 free-machining brass product datasheet'
    type: datasheet
    url: https://www.smithmetal.com/pdf/brass/c36000.pdf
    year: 2023
  - title: 'National Bronze: C36000 Free Cutting Brass Bar, applications and composition'
    type: datasheet
    url: https://nationalbronze.com/C36000_Free_Cutting_Brass.php
  - title: 'Wikipedia: Brass (lead content, dezincification, season cracking, alloy composition table)'
    type: database
    url: https://en.wikipedia.org/wiki/Brass
    year: 2026
  - title: 'The Hendrix Group archive: stress corrosion cracking (season cracking) of brasses'
    type: report
    url: https://hghouston.com/archive/material-property-data/copper-and-copper-alloys/brasses/sc-cracking
  - title: 'ATSDR ToxFAQs: Lead'
    type: report
    url: https://wwwn.cdc.gov/TSP/ToxFAQs/ToxFAQsDetails.aspx?faqid=93&toxid=22
  - title: 'USGS Mineral Commodity Summaries 2026: Copper'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-copper.pdf
    year: 2026
  - title: 'USGS Mineral Commodity Summaries 2026: Zinc'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-zinc.pdf
    year: 2026
  - title: 'USGS Mineral Commodity Summaries 2026: Lead'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-lead.pdf
    year: 2026
  - title: 'Wieland: brass alloys, machining brass table (EN designation, EN No., ASTM UNS-No., JIS-No.)'
    type: datasheet
    url: https://www.wieland.com/products/brass-alloys
  - title: 'Aalco Product Guide: copper, brass and bronze, wrought copper-zinc-lead alloys and BS to EN conversion table'
    type: datasheet
    url: https://www.aalco.co.uk/literature/files/aalco-copper-brass-bronze.pdf
gaps:
  - Elastic (Young's) modulus not recorded. The Fisk page prints the modulus of elasticity as 97 Mpa and 14 ksi, which is about 1000 times too low for brass, so the figure is treated as a printing error; no other source for the elastic modulus was read.
  - No GHS classification or exposure limit for lead was read. PubChem, NIOSH, OSHA and the ATSDR lead profile returned challenge or rejection pages to the fetcher, so the lead hazard rests on the ATSDR ToxFAQ and Wikipedia.
  - 'Lead content range differs by source: Aviva, Fisk and National Bronze give 2.5 to 3.0 wt% lead, while Wikipedia''s C360 row gives 2.5 to 3.7 wt%. The ASTM B16 text (sold) and the EN 12164 standard were not opened, so the official range is not settled here.'
  - Strength by temper covers O60, H02 and H04 round rod (Fisk) and H02 bar 12.7 mm and under (Aviva). No hard or soft value for bar was read. The Smith range of 338 to 469 MPa tensile and 124 to 310 MPa yield gives no temper for each value, so it is not used. The National Bronze mechanical table did not extract cleanly from the page and is not used.
  - 'Hardness: only one range (H02 bar, HRB 60 to 80, from Aviva). No hardness for O60 or H04 was read. The benchmark name hardness_rockwell_b is not in the property canon.'
  - Machinability is a supplier's relative index with C36000 set at 100, not a measured property. The benchmark name machinability_rating is not in the property canon.
  - Electrical conductivity uses the snake_case name electrical_conductivity, which is not in the property canon. The Fisk metric value for the same row (0.15 MS·cm) does not convert, so only the 26 %IACS value is used.
  - 'Dezincification and season cracking: no depth, rate, threshold stress or time to failure for C36000 was in a page we could read. The Rimkus case study on failed C36000 plumbing fittings returned a blocked page to the fetcher and is not used.'
  - No atmospheric corrosion rate for C36000 was found in the pages read. The Copper Development Association page returned a forbidden page to the fetcher, so its alloy data sheet was not used.
  - 'No space-environment data for brass were read: no outgassing, atomic-oxygen, cold-welding or radiation result for C36000. The tags.environments list is empty for this reason. The habitats-and-suits application tag reflects plumbing fittings and fluid connectors only, which is our mapping; no source names a space use.'
  - Thermal conductivity and coefficient of thermal expansion from Fisk are not stated with a temper; the page gives one value for the alloy.
  - 'No CAS number: brass is identified by its UNS number, C36000, and no CAS source was read.'
  - Specific heat, Poisson's ratio and cast-form densities were not searched.
  - Lead is a recognised health hazard in the sources, but no lead-free brass value was taken from a page other than Aviva's own Model 3 comparison, which is a vendor's claim.
  - No media (images) were added to this profile; no image was fetched or checked in this run.
  - 'Recycling: no brass-specific recycling share was found; the copper summary''s statement that brass and wire-rod mills took about 80 % of scrap-recovered copper is the closest figure.'
  - 'Designations: JIS C3604 and ASTM B453 are not printed by any page read in this run (Fisk, National Bronze, Aviva, Smith, Wieland, the Aalco product guide, Concast, Wikipedia, Metals Supermarkets). copper.org and muellerbrass.com returned 403 and olinbrass.com does not resolve, so those pages may still hold these codes.'
  - 'Designations: BS CZ121 is not listed for C36000. The Aalco product guide prints CZ121Pb3 for CuZn39Pb3 (CW614N), a different alloy, and gives CZ124 as the nearest old BS equivalent of CuZn36Pb3; CZ124 is listed with note nearest equivalent.'
  - 'Designations: no ISO code, no Alloy 360 name and no product form for ASTM B16 is printed by any page read in this run.'
sources:
  fisk-ma36b:
    title: 'Fisk Alloy, C36000 Free-Cutting Brass (CuZn36Pb3), product MA36B: physical properties, pretempered round wire and round rod tables, composition'
    url: https://fiskalloy.com/product/ma36b/
    kind: datasheet
    license: Supplier web page (cited, not reproduced)
  aviva-c36000:
    title: 'Aviva Metals, C36000 free-machining brass product page: chemical composition, Model 3 comparison table, dezincification note'
    url: https://avivametals.com/products/c36000-free-machining-brass-free-cutting-brass
    kind: datasheet
    license: Supplier web page (cited, not reproduced)
  smith-c36000:
    title: Smiths Metal Centres, C36000 Free-Machining Brass product datasheet (2023)
    url: https://www.smithmetal.com/pdf/brass/c36000.pdf
    year: 2023
    kind: datasheet
    license: Supplier datasheet (cited, not reproduced)
  natbronze-c36000:
    title: 'National Bronze and Metals, C36000 Free Cutting Brass Bar: composition, nominal composition, applications'
    url: https://nationalbronze.com/C36000_Free_Cutting_Brass.php
    kind: datasheet
    license: Supplier web page (cited, not reproduced)
  wiki-brass:
    title: 'Brass (Wikipedia): lead content, dezincification, season cracking, alloy composition table'
    url: https://en.wikipedia.org/wiki/Brass
    year: 2026
    kind: web
    license: CC BY-SA 4.0 (cited, not reproduced)
  hgh-scc:
    title: 'The Hendrix Group, Material Property Data: copper and copper alloys, brasses, stress corrosion cracking'
    url: https://hghouston.com/archive/material-property-data/copper-and-copper-alloys/brasses/sc-cracking
    kind: web
    license: Technical archive page (cited, not reproduced)
  atsdr-lead:
    title: 'ATSDR ToxFAQs: Lead (Agency for Toxic Substances and Disease Registry, U.S. CDC)'
    url: https://wwwn.cdc.gov/TSP/ToxFAQs/ToxFAQsDetails.aspx?faqid=93&toxid=22
    kind: report
    license: U.S. government public domain (cited, not reproduced)
  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)
  usgs-mcs2026-zinc:
    title: 'Mineral Commodity Summaries 2026: Zinc'
    id: USGS MCS 2026, February 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-zinc.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  usgs-mcs2026-lead:
    title: 'Mineral Commodity Summaries 2026: Lead'
    id: USGS MCS 2026, February 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-lead.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  wieland-brass-alloys:
    title: 'Wieland: brass alloys, machining brass table (EN designation, EN No., ASTM UNS-No., JIS-No.)'
    url: https://www.wieland.com/products/brass-alloys
    kind: datasheet
    license: Manufacturer web page (cited, not reproduced)
  aalco-copper-brass-bronze:
    title: 'Aalco Product Guide: copper, brass and bronze, wrought copper-zinc-lead alloys and BS to EN conversion table'
    url: https://www.aalco.co.uk/literature/files/aalco-copper-brass-bronze.pdf
    kind: datasheet
    license: Stockist product guide (cited, not reproduced)
license: CC-BY-4.0
updated: '2026-10-24'
review:
  status: draft
  method: assistant
  checked_values: 23
  unreachable: 10
  caveats: 6
  note: 'Values were read by an AI assistant on 2026-10-24 from the pages and PDFs named in each entry. Unreachable to the fetcher (bot, challenge or forbidden pages): MakeItFrom (three C36000 pages), copper.org alloy 360 page, PubChem lead, NIOSH lead, OSHA lead, ATSDR lead profile, Rimkus C36000 case study, and Materials Plus. Caveats: strength values are minimum values from one supplier''s rod table and one supplier''s bar comparison, not from the ASTM B16 text; the lead range differs between sources (2.5 to 3.0 and 2.5 to 3.7 wt%); the hardness and machinability names are not in the property canon; dezincification and season-cracking statements are qualitative; no space-environment data; the Fisk elastic modulus is printed with a units error and was not recorded.'
story:
  risk_groups:
    - title: For people
      lead: The lead in C36000 is the main health concern in these sources. They give health effects of lead but no exposure limit for brass dust.
      level: 2
      verdict: Leaded alloy
      points:
        - label: Lead in the alloy
          line: C36000 has 2.5 to 3.0 % lead (Aviva and Fisk limits; Wikipedia gives 2.5 to 3.7 % for C360). The ATSDR says lead can affect almost every organ and system, and the U.S. Department of Health and Human Services considers lead and lead compounds reasonably anticipated to be human carcinogens.
        - label: Plumbing
          line: California defines lead-free brass as containing no more than 0.25 % lead (AB 1953), down from 4.0 % on 1 January 2010 (Wikipedia). Aviva says the U.S. plumbing industry replaced C36000 with lead-free alternatives from January 2010.
    - title: If it fails
      lead: The failure routes in these sources are chemical (water and ammonia) and, for the hard temper, mechanical.
      points:
        - label: Dezincification
          line: In water with chlorides, high temperature or soft quality, zinc leaves the alloy and a weak copper layer remains. Aviva says this can create catastrophic failures.
        - label: Season cracking
          line: Cold work leaves stress, and in an ammonia or amine atmosphere the alloy can crack. The Hendrix Group describes the crack pattern for simple alpha brass, not for C36000.
        - label: Hard temper
          line: The H04 hard temper reaches 480 MPa minimum tensile strength, but its elongation is only 4 % minimum, so there is little room for bending.
    - title: Handling and storage
      points:
        - label: Pick the temper
          line: Annealed O60 round rod has 330 MPa minimum tensile and 15 % elongation. Half-hard H02 has 390 MPa and 7 %. Hard H04 has 480 MPa and 4 %.
        - label: Stress relief
          line: Stress-relieve parts after cold work, as the Hendrix Group advises, and keep them out of ammonia and amine atmospheres.
  why: Free-cutting brass is chosen for ease of machining. National Bronze says its two-phase structure forms broken chips instead of long coils, and that the lead content adds internal lubrication against the cutting tool. The alloy is rated 100 on the supplier machinability scale. It conducts electricity at 26 %IACS and heat at 116 W/(m·K) at 20 °C (Fisk MA36B). Its density is 8.5 g/cm3. The lead content is the reason it falls outside California's lead-free plumbing rule, and it is the main health concern in these sources.
  uses:
    - where: Screw-machine parts and fasteners
      line: National Bronze lists screw machine products, valve components, fasteners, fittings, hardware, fluid connectors and automotive sensor housings as C36000 applications. Smith lists machine screw parts, high-volume parts, plumbing components and fluid connectors.
    - where: Fittings and fluid connectors
      line: Smith says C36000 offers good corrosion resistance and is readily brazed or soldered, and lists fittings and adaptors and fluid connectors among its applications. These are terrestrial uses; no source names a space system.
  can_do:
    - label: Cut fast
      value: machinability rated 100
      line: Aviva and National Bronze give C36000 a machinability rating of 100, and National Bronze calls it the standard against which other metals are measured. The scale is the supplier's, not a measured value.
    - label: Carry current
      value: 26 %IACS
      line: Electrical conductivity is 26 %IACS when annealed (Fisk) and 26 % in the half-hard H02 bar (Aviva). Fisk prints an electrical resistivity of 6.63 µΩ·cm at 20 °C when annealed.
    - label: Carry heat
      value: 116 W/(m·K)
      benchmark: thermal_conductivity
      line: Thermal conductivity is 116 W/(m·K) at 20 °C (Fisk MA36B, metric column).
    - label: Strength by temper
      value: 330 to 480 MPa minimum tensile
      line: Round rod minimum tensile strength is 330 MPa annealed, 390 MPa half hard and 480 MPa hard (Fisk). Aviva gives 395 MPa minimum for half-hard bar 12.7 mm and under.
    - label: Weight
      value: 8.5 g/cm3
      benchmark: density
      line: Density is 8.5 g/cm3 (Fisk MA36B, metric column).
    - label: Melting
      value: 954 to 1049 °C
      line: The solidus is 954 °C and the liquidus is 1049 °C (Fisk MA36B, metric column).
    - label: Expansion
      value: 20.5 ppm/K
      benchmark: cte
      line: The coefficient of thermal expansion is 20.5 ppm/K over 20 to 300 °C (Fisk MA36B, printed as per °C).
  compare: The [copper profile](/profiles/copper/) covers the pure metal, and it is the natural comparison for conductivity and density. Within the Aviva comparison, its lead-free Model 3 alloy has a higher minimum yield strength and a higher electrical conductivity than C36000 half-hard bar 12.7 mm and under (170 MPa and 26 %IACS for C36000). It has a lower minimum tensile strength and a lower machinability rating (395 MPa and 100 for C36000). These are Aviva's own figures for its own alloy, so they are a vendor's comparison and not an independent test.
  compare_rows:
    - label: Density
      benchmark: density
    - label: Thermal conductivity
      benchmark: thermal_conductivity
    - label: Thermal expansion
      benchmark: cte
  handling:
    - 'Specify the temper: strength runs from 330 MPa minimum tensile in annealed O60 round rod to 480 MPa in hard H04 round rod.'
    - Stress-relieve after cold work (pressing, spinning, drawing, bending), and keep parts out of ammonia and amine atmospheres.
    - The alloy contains lead, so machining chips and dust are lead sources; the ATSDR advice to avoid lead exposure applies to them (this is our inference from the advice, not a statement in the source).
  good_for:
    - Machined parts in volume, where machinability rated 100 is the main selection criterion.
    - Fittings and connectors that need 330 to 480 MPa minimum tensile strength, chosen by temper.
    - 'Brazed or soldered assemblies: Smith rates the alloy as readily brazed or soldered.'
  watch_out:
    - Lead at 2.5 to 3.0 % puts the alloy outside California's 0.25 % limit for lead-free plumbing brass.
    - Dezincification in water and season cracking in ammonia, both caused by the zinc content and by stress.
    - Hard H04 round rod stretches only 4 % minimum, which limits forming.
    - The shear modulus of 37 GPa is a typical value with no temper stated, and no elastic modulus is recorded (see gaps).
  verdict: Free-cutting brass C36000 is the machinability reference among brasses, rated 100 on the supplier scale. It conducts at 26 %IACS and gives 330 to 480 MPa minimum tensile strength across the O60 to H04 tempers. Its 2.5 to 3.0 % lead rules it out of California's lead-free plumbing brass, and its zinc content invites dezincification in water and season cracking in ammonia. No corrosion rate, no space-environment result and no elastic modulus were found in the pages read.
  recipe:
    line: Free-cutting brass is a copper-zinc alloy with 2.5 to 3.0 % lead. National Bronze says its two-phase structure forms broken chips. Wikipedia says lead is often added at about 2 % to improve machinability, and that it forms globules at the grain boundaries as the casting cools.
    parts:
      - name: Copper
        symbol: Cu
        share: 60.0 to 63.0 wt%
        role: Main metal and matrix of the alloy (limits from Aviva, Fisk and Smith).
      - name: Zinc
        symbol: Zn
        share: remainder (nominal 35.4 wt% on the National Bronze page)
        role: The alloying element that makes the brass. Above 15 % zinc, dezincification risk rises (Aviva).
      - name: Lead
        symbol: Pb
        share: '2.5 to 3.0 wt% (Wikipedia C360 row: 2.5 to 3.7 wt%)'
        role: Added for machinability; National Bronze says the lead content adds internal lubrication against the cutting tool.
      - name: Iron
        symbol: Fe
        share: 0.35 wt% maximum
        role: Impurity limit printed on the Aviva, Fisk and National Bronze pages.