spore: profile
id: gilding-metal
spore_version: 0.2
family: copper-alloys
name: Gilding metal 95/5
abbreviation: C21000
role: cold-working copper-zinc alloy, high copper
category: metals
type: copper-alloys
summary: |
  Gilding metal 95/5 (UNS C21000, CuZn5, EN CW500L) is a copper-zinc alloy with 95 % copper and 5 % zinc. Wieland calls it the historic penny alloy and says it is the usual choice for deep-drawn bullet jackets and coined products. Its density is 8.86 g/cm3, its thermal conductivity is 234 W/(m·K) at room temperature and its conductivity is 56 %IACS. Annealed tensile strength runs from 235 to 275 MPa (Wieland) and the spring temper H08 from 415 to 470 MPa (Wieland). The CuZn10 grade (C22000, commercial bronze, the tombac range) is covered as a second grade in this file: Aurubis gives 248 to 290 MPa annealed and 476 to 531 MPa in H08. CuZn15 (C23000) is named in the Wieland table, but no property of it was read.
best_for: Deep-drawn and coined parts such as bullet jackets, coins, connectors and fasteners, where copper is too soft or too costly and moderate conductivity with extra strength is enough (Wieland)
weakest_at: Season cracking in ammonia or amine atmospheres when cold-forming stress is left in the part, and poor machinability (Fisk index 1, poor)
identity:
  formula: 'CuZn5, UNS C21000: copper 94.0 to 96.0 wt%, lead 0.05 wt% maximum, iron 0.05 wt% maximum, zinc remainder'
  source: aviva-c21000
  where: Chemical Composition table on the Aviva C21000 page (Cu 94.0 to 96.0, Pb 0.05 max, Fe 0.05 max, Zn rem); the same limits appear on the Fisk C21000 PDF, and the nominal Cu 95 and Zn 5 appear on the Wieland M05 datasheet.
  designations:
    - system: UNS
      code: C21000
      source: wieland-m05
      where: 'Datasheet heading: CuZn5 | C21000 | CW500L'
    - system: EN name
      code: CW500L
      source: wieland-m05
      where: 'Datasheet heading: CuZn5 | C21000 | CW500L'
    - system: EN name
      code: CuZn5
      source: wieland-m05
      where: 'Datasheet heading: CuZn5 | C21000 | CW500L'
    - system: JIS
      code: C2100
      source: wieland-brass-table
      where: Brass alloys table, row M05, JIS-No. column
    - system: ASTM
      code: B36
      note: plate, sheet, strip and rolled bar
      source: fisk-c21000-pdf
      where: 'Specifications box: ASTM B36'
    - system: ASTM
      code: B134
      note: wire
      source: fisk-c21000-pdf
      where: 'Specifications box: ASTM B134'
    - system: Trade name
      code: Gilding Metal
      source: wieland-m05
      where: 'Opening paragraph: Known as Gilding Metal, C21000'
tags:
  environments: []
  stresses: []
  applications:
    - electronics-and-chips
    - mechanisms
properties:
  - benchmark: density
    label: Density, C21000 (Wieland)
    value: 8.86
    unit: g/cm3
    scope: material
    conditions:
      grade: C21000 (CuZn5)
      temperature: room temperature (reference value)
      unit_in_source: 0.320 lb/in3 (Wieland US column)
    method: Value printed in the metric column of a manufacturer's reference table; the Aviva page prints specific gravity 8.86 for the same alloy
    status: ground
    source: wieland-m05
    where: Physical properties table, Density row, metric column
  - benchmark: thermal_conductivity
    label: Thermal conductivity, C21000 (Wieland)
    value: 234
    unit: W/(m·K)
    scope: material
    conditions:
      grade: C21000 (CuZn5)
      temperature: room temperature (reference value)
      unit_in_source: 135 Btu.ft/(ft2.h.°F) (Wieland US column)
    method: Value printed in the metric column of the Wieland physical properties table; Fisk prints the same 234 W/m K at 20 °C on its product page
    status: ground
    source: wieland-m05
    where: Physical properties table, Thermal conductivity row, metric column
  - benchmark: electrical_conductivity
    label: Electrical conductivity, annealed C21000 (Wieland)
    value: 56
    unit: '%IACS'
    scope: material
    conditions:
      grade: C21000 (CuZn5)
      temperature: room temperature (reference value)
      unit_in_source: 33 MS/m (Wieland metric column)
    method: Value printed in the %IACS column of the Wieland table; Fisk prints the same 56 % IACS at 68 °F
    status: ground
    source: wieland-m05
    where: Physical properties table, Electrical conductivity row, %IACS column
  - benchmark: electrical_resistivity
    label: Electrical resistivity, annealed C21000 (Fisk)
    value: 3.08
    unit: µΩ·cm
    scope: material
    conditions:
      grade: C21000 (Fisk Gilding 95 %)
      temper: annealed
      temperature: 20 °C
      unit_in_source: 18.5 Ω·cir-mil/ft at 68 °F (Fisk English column)
    method: Value printed in the metric column of the Fisk physical properties table on the product page
    status: ground
    source: fisk-c21000
    where: Physical Properties table, Electrical Resistivity (Annealed) row, metric column
  - benchmark: melting_point
    label: Solidus, C21000 (Fisk)
    value: 954
    unit: °C
    scope: material
    conditions:
      grade: C21000 (Fisk Gilding 95 %)
      unit_in_source: 1,750 °F (English column)
      pressure: not stated
    method: Value printed in the metric column of the Fisk physical properties table; the Aviva page prints a solidus of 1920 °F, which conflicts and is not used (see gaps)
    status: ground
    source: fisk-c21000
    where: Physical Properties table, Melting Point (Solidus) row, metric column
  - benchmark: melting_point
    label: Liquidus, C21000 (Fisk)
    value: 1049
    unit: °C
    scope: material
    conditions:
      grade: C21000 (Fisk Gilding 95 %)
      unit_in_source: 1,920 °F (English column)
      pressure: not stated
    method: Value printed in the metric column of the Fisk physical properties table on the product page
    status: ground
    source: fisk-c21000
    where: Physical Properties table, Melting Point (Liquidus) row, metric column
  - benchmark: cte
    label: Coefficient of thermal expansion, C21000 (Wieland)
    value: 18
    unit: ppm/K
    scope: material
    conditions:
      grade: C21000 (CuZn5)
      temperature: 0 to 300 °C
      unit_in_source: 10.0 10-6/°F (Wieland US column)
    method: Printed as 18.0 10-6/K in the Wieland reference table, between 0 and 300 °C; the number is copied without conversion because 10-6/K equals ppm/K
    status: ground
    source: wieland-m05
    where: Physical properties table, Coefficient of thermal expansion row, metric column, footnote for 0 to 300 °C
  - benchmark: elastic_modulus
    label: Modulus of elasticity, C21000 (Wieland)
    value: 117
    unit: GPa
    scope: material
    conditions:
      grade: C21000 (CuZn5)
      temperature: room temperature (reference value)
      unit_in_source: 17,000 ksi (Wieland US column)
    method: Value printed in the metric column of the Wieland reference table
    status: ground
    source: wieland-m05
    where: Physical properties table, Modulus of elasticity row, metric column
  - benchmark: specific_heat
    label: Specific heat, C21000 (Wieland)
    value: 0.38
    unit: J/(g·K)
    scope: material
    conditions:
      grade: C21000 (CuZn5)
      temperature: room temperature (reference value)
      unit_in_source: 0.091 Btu/(lb.°F) (Wieland US column)
    method: Value printed in the metric column of the Wieland reference table, in J/(g.K); not converted
    status: ground
    source: wieland-m05
    where: Physical properties table, Specific heat row, metric column
  - benchmark: poissons_ratio
    label: Poisson's ratio, C21000 (Wieland)
    value: 0.34
    unit: '-'
    scope: material
    conditions:
      grade: C21000 (CuZn5)
      temperature: room temperature (reference value)
    method: Printed without a unit in the Wieland reference table
    status: ground
    source: wieland-m05
    where: Physical properties table, Poisson's ratio row
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, annealed C21000, sheet and strip (Wieland)
    value: 235
    value_high: 275
    unit: MPa
    scope: material
    conditions:
      grade: C21000 (CuZn5)
      temper: annealed (Wieland), ASTM B36 temper
      product_form: sheet, strip and rolled bar
      unit_in_source: 34-40 ksi (Wieland US column)
    method: Range printed in the mechanical properties table by temper, metric column; the table note says the values are to ASTM B36, and the bracketed yield and elongation figures are for information only and are not used
    status: ground
    source: wieland-m05
    where: Mechanical properties table, Annealed row, Tensile strength Rm column (MPa)
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, half-hard H02, sheet and strip (Wieland)
    value: 290
    value_high: 360
    unit: MPa
    scope: material
    conditions:
      grade: C21000 (CuZn5)
      temper: H02, half hard
      product_form: sheet, strip and rolled bar
      unit_in_source: 42-52 ksi (Wieland US column)
    method: Range printed in the mechanical properties table by temper, metric column, marked as to ASTM B36
    status: ground
    source: wieland-m05
    where: Mechanical properties table, H02 row, Tensile strength Rm column (MPa)
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, hard H04, sheet and strip (Wieland)
    value: 345
    value_high: 405
    unit: MPa
    scope: material
    conditions:
      grade: C21000 (CuZn5)
      temper: H04, hard
      product_form: sheet, strip and rolled bar
      unit_in_source: 50-59 ksi (Wieland US column)
    method: Range printed in the mechanical properties table by temper, metric column, marked as to ASTM B36
    status: ground
    source: wieland-m05
    where: Mechanical properties table, H04 row, Tensile strength Rm column (MPa)
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, spring H08, sheet and strip (Wieland)
    value: 415
    value_high: 470
    unit: MPa
    scope: material
    conditions:
      grade: C21000 (CuZn5)
      temper: H08, spring
      product_form: sheet, strip and rolled bar
      unit_in_source: 60-68 ksi (Wieland US column)
    method: Range printed in the mechanical properties table by temper, metric column, marked as to ASTM B36
    status: ground
    source: wieland-m05
    where: Mechanical properties table, H08 row, Tensile strength Rm column (MPa)
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, half-hard H02 round wire (minimum)
    value: 330
    bound: lower
    unit: MPa
    scope: material
    conditions:
      grade: C21000 (Fisk Gilding 95 %)
      temper: H02, 1/2 hard
      product_form: round wire, mill limits 0.0254 to 3.264 mm
      measure: minimum
      unit_in_source: 49.0 ksi (English column)
    method: Minimum value printed in the Fisk round wire temper table, metric column; wire, so not comparable with the flat-product rows
    status: ground
    source: fisk-c21000
    where: Round Wire temper table, metric block, H02 row, Tensile Strength Min (MPa)
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, hard H04 round wire (minimum)
    value: 420
    bound: lower
    unit: MPa
    scope: material
    conditions:
      grade: C21000 (Fisk Gilding 95 %)
      temper: H04, hard
      product_form: round wire, mill limits 0.0254 to 3.264 mm
      measure: minimum
      unit_in_source: 61.0 ksi (English column)
    method: Minimum value printed in the Fisk round wire temper table, metric column; wire, not sheet
    status: ground
    source: fisk-c21000
    where: Round Wire temper table, metric block, H04 row, Tensile Strength Min (MPa)
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, spring H08 round wire (minimum)
    value: 490
    bound: lower
    unit: MPa
    scope: material
    conditions:
      grade: C21000 (Fisk Gilding 95 %)
      temper: H08, spring
      product_form: round wire, mill limits 0.0254 to 3.264 mm
      measure: minimum
      unit_in_source: 72.0 ksi (English column)
    method: Minimum value printed in the Fisk round wire temper table, metric column; the table gives no maximum for this temper
    status: ground
    source: fisk-c21000
    where: Round Wire temper table, metric block, H08 row, Tensile Strength Min (MPa)
  - benchmark: elongation
    label: Elongation, annealed OS050 (Aviva)
    value: 45
    unit: '%'
    scope: material
    conditions:
      grade: C21000 (Aviva)
      temper: OS050, nominal grain size 0.050 mm, annealed
      gauge_length: 0.04 in section
      basis: typical value, 68 °F
    method: Typical value (Typ) printed in the Aviva mechanical properties by temper table; the page is US units only and no metric column exists
    status: ground
    source: aviva-c21000
    where: Mechanical Properties by Temper table, OS050 row, Elong. (%) column
  - benchmark: elongation
    label: Elongation, half-hard H02 (Aviva)
    value: 12
    unit: '%'
    scope: material
    conditions:
      grade: C21000 (Aviva)
      temper: H02, half hard
      gauge_length: 0.04 in section
      basis: typical value, 68 °F
    method: Typical value (Typ) printed in the Aviva mechanical properties by temper table
    status: ground
    source: aviva-c21000
    where: Mechanical Properties by Temper table, 1/2 Hard (H02) row, Elong. (%) column
  - benchmark: elongation
    label: Elongation, hard H04 (Aviva)
    value: 5
    unit: '%'
    scope: material
    conditions:
      grade: C21000 (Aviva)
      temper: H04, hard
      gauge_length: 0.04 in section
      basis: typical value, 68 °F
    method: Typical value (Typ) printed in the Aviva mechanical properties by temper table
    status: ground
    source: aviva-c21000
    where: Mechanical Properties by Temper table, Hard (H04) row, Elong. (%) column
  - benchmark: elongation
    label: Elongation, spring H08 (Aviva)
    value: 4
    unit: '%'
    scope: material
    conditions:
      grade: C21000 (Aviva)
      temper: H08, spring
      gauge_length: 0.04 in section
      basis: typical value, 68 °F
    method: Typical value (Typ) printed in the Aviva mechanical properties by temper table
    status: ground
    source: aviva-c21000
    where: Mechanical Properties by Temper table, Spring (H08) row, Elong. (%) column
  - benchmark: machinability_rating
    label: Machinability rating, C21000 (Aviva)
    value: 20
    unit: '%'
    scope: material
    conditions:
      grade: C21000
      temper: not stated
      basis: relative index; the base (100 = reference alloy) is not printed on this page
    method: Index printed in the Aviva fabrication table; a relative rating, not a measured property. Fisk rates the same alloy 1 (poor) on its own scale, and the two scales are not compared
    status: ground
    source: aviva-c21000
    where: Fabrication properties, Machinability Rating row
  - benchmark: density
    label: Density, C22000 CuZn10 (Aurubis)
    value: 8.8
    unit: g/cm3
    scope: material
    conditions:
      grade: C22000 (CuZn10, tombac range)
      temperature: 20 °C
      unit_in_source: 0.318 lb/in3 (Aurubis US column)
    method: Value printed in the metric column of the Aurubis technical datasheet; Wieland's M10 datasheet prints 8.80 g/cm3, which is consistent
    status: ground
    source: aurubis-c22000
    where: Physical properties table, Density row, metric column
  - benchmark: melting_point
    label: Melting point, C22000 CuZn10 (Aurubis)
    value: 1043
    unit: °C
    scope: material
    conditions:
      grade: C22000 (CuZn10, tombac range)
      unit_in_source: 1910 °F (Aurubis US column)
      pressure: not stated
    method: Single melting point value printed in the Aurubis physical properties table; no solidus and liquidus pair is printed
    status: ground
    source: aurubis-c22000
    where: Physical properties table, Melting point row, metric column
  - benchmark: thermal_conductivity
    label: Thermal conductivity at 20 °C, C22000 CuZn10 (Aurubis)
    value: 189
    unit: W/(m·K)
    scope: material
    conditions:
      grade: C22000 (CuZn10, tombac range)
      temperature: 20 °C
      unit_in_source: 109 Btu/(ft h °F) (Aurubis US column)
    method: Value printed in the metric column of the Aurubis physical properties table; Wieland M10 prints 189 W/(m.K) for the same grade
    status: ground
    source: aurubis-c22000
    where: Physical properties table, Thermal conductivity at 20 °C row, metric column
  - benchmark: electrical_conductivity
    label: Electrical conductivity, soft C22000 CuZn10 (Aurubis)
    value: 44
    unit: '%IACS'
    scope: material
    conditions:
      grade: C22000 (CuZn10, tombac range)
      temper: soft (the conductivity applies to the soft condition only)
      temperature: 20 °C
    method: Value printed in the %IACS column of the Aurubis physical properties table; the same row gives 26 MS/m, which Wieland prints as 25 MS/m, so the %IACS value is used
    status: ground
    source: aurubis-c22000
    where: Physical properties table, Electrical conductivity row, %IACS column
  - benchmark: cte
    label: Coefficient of thermal expansion, C22000 CuZn10 (Aurubis)
    value: 18.4
    unit: ppm/K
    scope: material
    conditions:
      grade: C22000 (CuZn10, tombac range)
      temperature: 20 °C
      unit_in_source: 10.2 10-6/°F (Aurubis US column)
    method: Printed as 18.4 10-6/K in the metric column of the Aurubis table; the same column header also gives the 20 °C condition
    status: ground
    source: aurubis-c22000
    where: Physical properties table, Coef. of therm exp. row, metric column
  - benchmark: elastic_modulus
    label: Modulus of elasticity, C22000 CuZn10 (Aurubis)
    value: 117
    unit: GPa
    scope: material
    conditions:
      grade: C22000 (CuZn10, tombac range)
      temperature: 20 °C
      unit_in_source: 17 x 1000 ksi (Aurubis US column)
    method: Value printed in the GPa column of the Aurubis physical properties table
    status: ground
    source: aurubis-c22000
    where: Physical properties table, Mod. of elasticity row, GPa column
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, soft C22000 CuZn10 sheet (Aurubis)
    value: 248
    value_high: 290
    unit: MPa
    scope: material
    conditions:
      grade: C22000 (CuZn10, tombac range)
      temper: soft
      product_form: sheet and strip (Aurubis leaflet, no form stated for the row)
      unit_in_source: 36-42 ksi (Aurubis US column)
    method: Range printed in the Aurubis mechanical properties table, metric column; the table note says other tempers are available on request, and no minimum is printed
    status: ground
    source: aurubis-c22000
    where: Mechanical properties table, Soft row, Tensile strength Rm column (MPa)
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, H04 C22000 CuZn10 sheet (Aurubis)
    value: 393
    value_high: 455
    unit: MPa
    scope: material
    conditions:
      grade: C22000 (CuZn10, tombac range)
      temper: H04
      product_form: sheet and strip (Aurubis leaflet, no form stated for the row)
      unit_in_source: 57-66 ksi (Aurubis US column)
    method: Range printed in the Aurubis mechanical properties table, metric column
    status: ground
    source: aurubis-c22000
    where: Mechanical properties table, H04 row, Tensile strength Rm column (MPa)
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, H08 C22000 CuZn10 sheet (Aurubis)
    value: 476
    value_high: 531
    unit: MPa
    scope: material
    conditions:
      grade: C22000 (CuZn10, tombac range)
      temper: H08
      product_form: sheet and strip (Aurubis leaflet, no form stated for the row)
      unit_in_source: 69-77 ksi (Aurubis US column)
    method: Range printed in the Aurubis mechanical properties table, metric column
    status: ground
    source: aurubis-c22000
    where: Mechanical properties table, H08 row, Tensile strength Rm column (MPa)
  - benchmark: elongation
    label: Elongation, soft C22000 CuZn10 (Aurubis)
    value: 47
    unit: '%'
    scope: material
    conditions:
      grade: C22000 (CuZn10, tombac range)
      temper: soft
      gauge_length: 2 in
    method: Value printed in the nominal elongation column of the Aurubis mechanical properties table (2 in gauge)
    status: ground
    source: aurubis-c22000
    where: Mechanical properties table, Soft row, Elongation 2 in column
corrosion:
  - environment: Ammonia or amine atmospheres with tensile stress (season cracking)
    headline: Brass season cracking is the classic failure of cold-formed copper-zinc alloys in ammonia. No rating for gilding metal was printed in the sources read.
    effect: The Hendrix Group says stress corrosion cracking needs both a high tensile stress and a specific corrosive environment, which for brasses is usually ammonia or amines, and that drawing and bending leave internal stresses that cause cracking unless they are removed by stress relief. The same article recommends low-zinc alloys over high-zinc alloys where service allows, and says the higher the copper content, the better the resistance. C21000 has 5 % zinc, so it sits at the low-zinc, high-copper end. No threshold stress or time to crack for C21000 is printed in the sources.
    rating: unknown
    conditions:
      basis: qualitative description for brasses in general; no rating or threshold for C21000 is printed in the sources
      test_example: 'Accelerated test cited by the Hendrix Group: air containing 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, cold working and copper content; the Hendrix test paragraph
  - environment: Outdoor exposure and dezincification (CuZn10, tombac range)
    headline: Aurubis says the 90/10 alloy has excellent resistance to stress-corrosion cracking and to dezincification.
    effect: The Aurubis datasheet for C22000 says its excellent resistance to stress-corrosion cracking and dezincification makes it suitable as an engineering alloy, widely used for ammunition components and for applications requiring outdoor exposure. No dezincification depth or test result is printed, and the claim is a supplier statement, not a measured rate.
    rating: low
    conditions:
      basis: supplier statement for C22000, not measured data; no dezincification test condition is printed
    source: aurubis-c22000
    where: Description paragraph, first sentences
risks:
  hazards:
    - text: 'Lead: C21000 contains 0.05 wt% lead at most (Aviva and Fisk limits). The ATSDR ToxFAQ says lead can affect almost every organ and system in the body and that HHS considers lead and lead compounds reasonably anticipated to be human carcinogens. No GHS code for the alloy was read.'
      ghs: []
      source: atsdr-lead
      where: ToxFAQs sections on health effects and cancer
  failure_risks:
    - mode: Season cracking in ammonia
      trigger: Tensile stress from cold forming (drawing, pressing, spinning, bending) together with an ammonia or amine atmosphere
      consequence: Cracking, which the Hendrix Group says is liable to occur in drawn tube that has not been stress-relieved
      severity: moderate
      source: hgh-scc
      where: Cold working and stress relief sections
    - mode: Poor machinability
      trigger: Machining or tool cutting of the alloy in a fabrication process
      consequence: Fisk rates machinability 1 (poor) on its fabrication index, and Aviva gives a machinability rating of 20 on its relative scale, so the alloy is a poor choice where machining is the main process
      severity: low
      source: fisk-c21000
      where: Fabrication Index table, Machinability row
  side_effects: []
  handling:
    - text: 'Specify the temper: Wieland gives annealed sheet 235 to 275 MPa tensile, H02 290 to 360 MPa, H04 345 to 405 MPa and H08 415 to 470 MPa.'
      source: wieland-m05
      where: Mechanical properties table
    - text: Anneal between 427 and 788 °C to soften the alloy; Fisk gives the annealing range as 800 to 1450 °F, which is 427 to 788 °C in the metric column.
      source: fisk-c21000
      where: Physical Properties table, Annealing Range rows
    - text: Stress-relieve after cold forming. The Hendrix Group gives a general range of one half to one hour at 250 to 300 °C for brasses, and says the optimum depends on the alloy.
      source: hgh-scc
      where: Stress relief paragraph
    - text: Keep parts out of ammonia and amine atmospheres in service.
      source: hgh-scc
      where: Environment section
    - text: Machining chips and dust from the alloy contain lead at up to 0.05 %; the ATSDR advice to avoid lead exposure applies (this is our inference from the advice, not a statement in the source).
      source: atsdr-lead
      where: How can I protect my family from lead exposure
  mitigations:
    - text: The Hendrix Group says the higher the copper content, the better the resistance to stress corrosion cracking, and recommends low-zinc alloys over high-zinc alloys where service and manufacture allow. C21000 is 95 % copper.
      source: hgh-scc
      where: Effect of composition section
    - text: Choose a stress-relieved or annealed temper for parts that are formed and then exposed to ammonia or amines.
      source: hgh-scc
      where: Cold working and stress relief sections (this is our summary of the advice, not a quote)
uses:
  - application: electronics-and-chips
    device: Electrical connectors and AC motor rotor bars
    example: Aviva lists connectors under electrical uses, citing electrical and thermal conductivity, corrosion resistance and formability, and lists rotor bars for AC motors citing brazability and electrical resistivity. Wieland says the alloy is a valuable option for electrical applications where performance requirements preclude standard copper. These are terrestrial uses; no source names a space system.
    source: aviva-c21000
    where: Typical Uses list, Electrical row (Connectors and Rotor Bars, AC Motors); Wieland M05 opening paragraph
  - application: mechanisms
    device: Fasteners and connector components
    example: Fisk lists connector components and fasteners as the uses of C21000, and Aviva lists fasteners, citing appearance, corrosion resistance and formability. These are terrestrial uses; no source names a space system.
    source: fisk-c21000
    where: Alloy description paragraph (Listed uses); Aviva Typical Uses list, Fasteners row
story:
  risk_groups:
    - title: For people
      lead: The lead in C21000 is the main health concern in these sources. The sources give the health effects of lead but no exposure limit for brass dust.
      level: 2
      verdict: Low-lead alloy
      points:
        - label: Lead in the alloy
          line: C21000 has 0.05 % lead at most (Aviva and Fisk). The ATSDR says lead can affect almost every organ and system, and HHS considers lead and lead compounds reasonably anticipated to be human carcinogens.
    - title: If it fails
      lead: The failure route in these sources is chemical (ammonia) and it is driven by residual stress from cold forming.
      points:
        - label: Season cracking
          line: Cold forming leaves stress, and in an ammonia or amine atmosphere the alloy can crack. The Hendrix Group describes the cracking, and recommends stress relief and low zinc.
    - title: Handling and storage
      points:
        - label: Pick the temper
          line: Annealed sheet is 235 to 275 MPa tensile (Wieland) and the spring temper H08 is 415 to 470 MPa. Elongation falls from 45 % in annealed OS050 (Aviva) to 4 % in H08.
        - label: Stress relief
          line: Stress-relieve parts after cold forming, as the Hendrix Group advises, and keep them out of ammonia and amine atmospheres.
  why: Gilding metal is chosen for deep drawing and coining. Wieland calls it the historic penny alloy and says it is the usual choice for deep-drawn bullet jackets and coined products. It has 95 % copper, a density of 8.86 g/cm3, a thermal conductivity of 234 W/(m·K) at room temperature and a conductivity of 56 %IACS. Its main weakness is season cracking in ammonia when cold-forming stress is left in the part.
  uses:
    - where: Electrical connectors and rotor bars
      line: Aviva lists connectors and rotor bars for AC motors as typical uses. Wieland names electrical applications where performance requirements preclude standard copper.
    - where: Fasteners and connector components
      line: Fisk lists connector components and fasteners. Aviva lists fasteners among its typical uses.
    - where: Bullet jackets, primers, coins and medals
      line: Aviva lists bullet jackets, primers, fuse caps and small arm ammunition, and coins, medals and tokens among its typical uses. Wikipedia says gilding metal was used for bullet jackets and for shell casings melted into US pennies. These are not space applications, and none of them fits the space application list, so they are not in the uses block.
  can_do:
    - label: Form cold
      value: Excellent cold-working rating
      line: Aviva and Fisk both rate the capacity for cold working as excellent, and Aviva gives 12 % elongation in half-hard H02 and 45 % in annealed OS050.
    - label: Carry heat
      value: 234 W/(m·K)
      benchmark: thermal_conductivity
      line: Thermal conductivity is 234 W/(m·K) at room temperature (Wieland, metric column).
    - label: Carry current
      value: 56 %IACS
      line: Electrical conductivity is 56 %IACS (Wieland and Aviva).
    - label: Strength by temper
      value: 235 to 470 MPa
      line: Wieland gives annealed sheet 235 to 275 MPa, half-hard H02 290 to 360 MPa, hard H04 345 to 405 MPa and spring H08 415 to 470 MPa.
    - label: Weight
      value: 8.86 g/cm3
      benchmark: density
      line: Density is 8.86 g/cm3 (Wieland, metric column).
    - label: Melting
      value: 954 to 1049 °C
      line: The solidus is 954 °C and the liquidus is 1049 °C (Fisk, metric column).
    - label: Expansion
      value: 18.0 ppm/K
      benchmark: cte
      line: The coefficient of thermal expansion is 18.0 ppm/K from 0 to 300 °C (Wieland).
  compare: The [copper profile](/profiles/copper/) covers the pure metal. The [cartridge brass profile](/profiles/cartridge-brass/) covers the 70/30 brass, which is stronger and has a higher zinc content, and it has the same season-cracking weakness. C21000 is the copper-rich end of the same family; the 90/10 CuZn10 grade (C22000) sits between the two.
  compare_rows:
    - label: Density
      benchmark: density
    - label: Thermal conductivity
      benchmark: thermal_conductivity
    - label: Thermal expansion
      benchmark: cte
  handling:
    - 'Specify the temper: annealed sheet is 235 to 275 MPa tensile and spring H08 is 415 to 470 MPa (Wieland).'
    - Stress-relieve after cold forming (drawing, pressing, spinning, bending), and keep parts out of ammonia and amine atmospheres.
    - The alloy contains lead at 0.05 % at most, so machining chips and dust are a lead source; the ATSDR advice applies (this is our inference from the advice, not a statement in the source).
  good_for:
    - Deep-drawn and coined parts, where good cold working and a ductile temper are the main criteria.
    - Electrical connectors and fasteners that need more strength than copper with moderate conductivity (56 %IACS).
    - Parts where a bronze colour and a copper-rich alloy are needed, as with the CuZn10 grade.
  watch_out:
    - Season cracking in ammonia or amine atmospheres when cold-forming stress is left in the part.
    - Machinability is poor (Fisk index 1), so do not choose this alloy for machined parts without a trial.
    - Lead at 0.05 % at most is still a health hazard in the sources.
    - No dezincification or space-environment data were read for C21000; the dezincification claim is for the 90/10 CuZn10 grade only.
  verdict: Gilding metal 95/5 is the copper-rich brass for deep drawing and coining. It conducts heat at 234 W/(m·K) and electricity at 56 %IACS, with annealed tensile strength of 235 to 275 MPa (Wieland) and spring temper up to 470 MPa. Its main weakness is season cracking in ammonia under residual stress, and the fix is a stress-relief anneal. The CuZn10 grade (C22000, the tombac range) is in the file as a second grade. No space-environment result, no C21000 corrosion rating and no copper GHS classification were found in the pages read.
  recipe:
    line: Gilding metal is a copper-zinc alloy with 94.0 to 96.0 wt% copper, zinc as the remainder (nominal 5 wt%), and at most 0.05 wt% lead and 0.05 wt% iron (Aviva and Fisk). Wieland prints the reference composition as Cu 95 % and Zn remainder. It is supplied as wrought strip, sheet, wire and rod (ASTM B36 and B134) and is made soft by annealing between 427 and 788 °C (Fisk).
    parts:
      - name: Copper
        symbol: Cu
        share: 94.0 to 96.0 wt% (nominal 95 wt%)
        role: Main metal and matrix of the alloy (limits from Aviva and Fisk; nominal from Wieland).
      - name: Zinc
        symbol: Zn
        share: remainder (nominal 5 wt%)
        role: The alloying element that makes the brass and raises strength above pure copper, with moderate conductivity still kept (Wieland).
      - name: Lead
        symbol: Pb
        share: 0.05 wt% maximum
        role: Impurity limit printed on the Aviva and Fisk pages.
      - name: Iron
        symbol: Fe
        share: 0.05 wt% maximum
        role: Impurity limit printed on the Aviva and Fisk pages.
documents:
  - title: 'Wieland: M05 CuZn5 | C21000 | CW500L rolled products datasheet (composition, physical and mechanical properties by temper)'
    type: datasheet
    url: https://www.wieland.com/hu/content/download/12535/file/M05_RP_EN.pdf
  - title: 'Wieland: brass alloys table, row M05 (CuZn5, CW500L, C21000, C2100) and row M10 (CuZn10, CW501L, C22000, C2200)'
    type: datasheet
    url: https://www.wieland.com/products/brass-alloys
  - title: 'Fisk Alloy: C21000 Gilding, 95% product page (physical properties, round wire temper table, alloy description)'
    type: datasheet
    url: https://fiskalloy.com/product/c21000/
  - title: 'Fisk Alloy: C21000 Gilding, 95% PDF (composition, specifications, fabrication index, round, square and rolled flat temper tables)'
    type: datasheet
    url: https://fiskalloy.com/pdf/c21000
  - title: 'Aviva Metals: C21000 Gilding Brass page (composition, physical properties, mechanical properties by temper, fabrication, typical uses)'
    type: datasheet
    url: https://www.avivametals.com/collections/copper-alloys/beryllium-copper/c21000-gilding-brass-1
  - title: 'Aurubis: Technical Datasheet C22000 (CuZn10), 18 08 US'
    type: datasheet
    url: https://www.aurubis.be/en/dam/jcr:50283e48-c222-4671-bde3-5bd1bd437df3/c22000-cuzn10-us.pdf
  - title: 'Wikipedia: Gilding metal (history, uses, composition)'
    type: database
    url: https://en.wikipedia.org/wiki/Gilding_metal
    year: 2026
  - title: 'Wikipedia: Tombac (name and history of high-copper brass; zinc range not used)'
    type: database
    url: https://en.wikipedia.org/wiki/Tombac
    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
gaps:
  - 'Copper and zinc GHS classification not read: PubChem was blocked by a browser check, and a copper granular SDS link returned a web page rather than a PDF. No GHS code is entered for the metal; the health entry relies on lead only.'
  - Fisk product page prints a metric density of 8.94 g/cm3 for C21000, which conflicts with Wieland (8.86 g/cm3) and Aviva (specific gravity 8.86). The Fisk value is not used.
  - Aviva prints a solidus of 1920 °F and a liquidus of 1950 °F, which conflicts with Fisk (solidus 1,750 °F or 954 °C, liquidus 1,920 °F or 1049 °C). The Fisk pair is used. Aviva prints the physical properties in US units only, so no Aviva metric value is used.
  - Fisk prints a modulus of rigidity and electrical conductivity in a unit that does not parse (0.33 MS·cm). Neither value is used. The Wieland value of 33 MS/m matches 56 %IACS.
  - Wieland prints yield strength and elongation for annealed and half-hard tempers only in brackets, marked for information only. Those figures are not recorded. Aviva gives yield in ksi (H02 40 ksi, H04 50 ksi) on a US-only page, and it is not recorded to keep one unit system per row.
  - Wieland prints hardness only in brackets (HV 45 to 75 for R230 and so on), so no hardness value is recorded.
  - Strength values for sheet and strip come from Wieland and Aviva; Fisk minimum values are for round wire and are not comparable with the flat-product rows. No ASTM B36 text was opened, so no specification minimum is recorded for C21000 sheet.
  - No dezincification statement or test for C21000 was read. The dezincification claim in the corrosion block is for the CuZn10 grade (C22000) only.
  - No threshold stress, time to crack or service rating for season cracking of C21000 was printed in the sources read.
  - 'Tombac: the name is not printed on the Wieland or Aurubis pages. Wikipedia gives a zinc range of 5 to 20 % for tombac, but that page carries maintenance tags, so the range is not used. The file covers CuZn10 (C22000) as the tombac-range grade.'
  - CuZn15 (C23000) is named in the Wieland brass alloys table (EN CW502L, JIS C2300), but no physical or mechanical property for it was read, so the file has no CuZn15 values.
  - Wieland prints CuZn10 CW501L; the CuZn5 CW500L code is confirmed by the Wieland M05 datasheet heading and the table row M05. The EN designation for CuZn5 is therefore CW500L, not CW501L.
  - Concast and the Aviva C21000 page with a metric column were not reachable (HTTP 404 on the URLs tried), so no Concast value is used.
  - No space-environment data (outgassing, atomic oxygen, cold welding, radiation) were read for C21000 or C22000. tags.environments is empty for this reason, and the applications listed are terrestrial uses.
  - No CAS number was read; the alloy is identified by its UNS number.
  - 'Media: no image was fetched or checked for this profile.'
sources:
  wieland-m05:
    title: 'Wieland, M05 CuZn5 | C21000 | CW500L rolled products datasheet: chemical composition, physical properties, mechanical properties by temper (ASTM B36), bendability, thermal stress relaxation'
    url: https://www.wieland.com/hu/content/download/12535/file/M05_RP_EN.pdf
    kind: datasheet
    license: Manufacturer datasheet (cited, not reproduced)
  wieland-brass-table:
    title: 'Wieland, brass alloys table: rows M05 (CuZn5, CW500L, C21000, C2100) and M10 (CuZn10, CW501L, C22000, C2200)'
    url: https://www.wieland.com/products/brass-alloys
    kind: datasheet
    license: Manufacturer web page (cited, not reproduced)
  aviva-c21000:
    title: 'Aviva Metals, C21000 Gilding Brass page: chemical composition, physical properties (US units), mechanical properties by temper (typical), fabrication ratings, typical uses, specifications'
    url: https://www.avivametals.com/collections/copper-alloys/beryllium-copper/c21000-gilding-brass-1
    kind: datasheet
    license: Supplier web page (cited, not reproduced)
  fisk-c21000:
    title: 'Fisk Alloy, C21000 Gilding, 95% product page: composition limits, physical properties (metric and US), round wire temper table, alloy description and listed uses'
    url: https://fiskalloy.com/product/c21000/
    kind: datasheet
    license: Supplier web page (cited, not reproduced)
  fisk-c21000-pdf:
    title: 'Fisk Alloy, C21000 Gilding, 95% PDF: composition, specifications (ASTM B36, ASTM B134), fabrication index, round, square and rolled flat temper tables'
    url: https://fiskalloy.com/pdf/c21000
    kind: datasheet
    license: Supplier document (cited, not reproduced)
  aurubis-c22000:
    title: 'Aurubis, Technical Datasheet C22000 (CuZn10), 18 08 US: composition, physical properties, mechanical properties by temper, fabrication, typical uses, specifications'
    url: https://www.aurubis.be/en/dam/jcr:50283e48-c222-4671-bde3-5bd1bd437df3/c22000-cuzn10-us.pdf
    kind: datasheet
    license: Manufacturer datasheet (cited, not reproduced)
  wiki-gilding-metal:
    title: 'Gilding metal (Wikipedia): composition, history, bullet jackets and US penny use'
    url: https://en.wikipedia.org/wiki/Gilding_metal
    year: 2026
    kind: web
    license: CC BY-SA 4.0 (cited, not reproduced)
  wiki-tombac:
    title: 'Tombac (Wikipedia): name, history and use of high-copper brass; page carries maintenance tags'
    url: https://en.wikipedia.org/wiki/Tombac
    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)
license: CC-BY-4.0
updated: '2026-10-26'
review:
  status: draft
  method: assistant
  checked_values: 33
  unreachable: 3
  caveats: 5
  note: 'Values were read by an AI assistant on 2026-10-26 from the pages and PDFs named in each entry. Unreachable or unusable: Aviva and Concast C21000 URLs tried first (HTTP 404), PubChem copper page (browser check), and a copper SDS link (returned HTML). Caveats: strength values for sheet are typical or range values from manufacturer tables, and the Fisk values are minimum values for round wire, not comparable with flat product; the Fisk metric density and melting point conflict with Wieland and Aviva and the Fisk melting pair is used; the Aurubis CuZn10 properties are for the soft condition and the H tempers, with form not stated per row; the season-cracking rating for C21000 is unknown in the sources.'