spore: profile
id: phosphor-bronze-c521
spore_version: 0.2
family: copper-alloys
name: Phosphor bronze C52100 (CuSn8)
abbreviation: C521
role: highest-tin wrought phosphor bronze for springs, connectors and slide bearings
category: metals
type: copper-alloys
summary: |
  Phosphor bronze C52100 (UNS C52100, CDA C521, EN CW453K, name CuSn8) is a wrought copper alloy with 7.00 to 9.00 % tin and 0.03 to 0.35 % phosphorus. Aurubis calls it the highest alloyed phosphor bronze in its family. Its density is 8.79 g/cm3 and its annealed electrical conductivity is 13 %IACS. The spring temper H08 has a tensile strength of 725 to 820 MPa and a minimum yield strength of 690 MPa, and H10 reaches 760 to 840 MPa. It is sold for springs, connectors, relays and slide bearings.
best_for: 'Springs and connectors: the H08 spring temper has 725 to 820 MPa tensile strength and 690 MPa minimum yield (Aurubis), and the alloy solders and brazes excellently'
weakest_at: Dust and fume when cut, ground or welded (Fisk SDS); the only seawater corrosion rate read is an unnamed-test manufacturer claim (jtcopper)
identity:
  formula: 'Cu-Sn-P wrought alloy, UNS C52100 (CuSn8): copper remainder, tin 7.00 to 9.00 %, phosphorus 0.03 to 0.35 %; lead 0.05 max, zinc 0.20 max, iron 0.10 max (wt %)'
  source: concast-c52100
  where: Chemical composition table, ASTM B139/B139M-12(2024), C52100 row (concast.com); the jtcopper page prints the same tin, phosphorus, iron, lead and zinc limits
  designations:
    - system: UNS
      code: C52100
      source: aurubis-c52100
      where: 'Header, Comparable standards line: UNS C52100'
    - system: CDA
      code: C521
      source: concast-c52100
      where: Similar-specification table, C52100 row, CDA column
    - system: EN name
      code: CW453K
      source: aurubis-c52100
      where: 'Header, Comparable standards line: EN CW453K'
    - system: EN name
      code: CuSn8
      source: aurubis-c52100
      where: Title line, C52100 (CuSn8)
    - system: EN name
      code: CuSn8P
      source: concast-c52100
      where: Opening sentence, C521 also designated as CuSn8P
    - system: BS
      code: PB104
      source: concast-c52100
      where: Opening sentence, C521 also designated as PB104
    - system: JIS
      code: C5210
      source: jtcopper-c52100
      where: Other designations line, JIS C5210
    - system: ASTM
      code: B139
      note: rod and bar
      source: concast-c52100
      where: Similar-specification table, C52100 row, ASTM column (ASTM B139/B139M)
tags:
  environments: []
  stresses: []
  applications:
    - electronics-and-chips
    - mechanisms
    - structures
properties:
  - benchmark: density
    label: Density, phosphor bronze C52100
    value: 8.79
    unit: g/cm3
    scope: material
    conditions:
      grade: C52100 (CuSn8)
      temperature: 20 °C
      unit_in_source: 0.318 lb/in3 at 20 °C
    method: Value printed in a manufacturer technical datasheet
    status: ground
    source: aurubis-c52100
    where: Physical properties table, row Density, metric value
  - benchmark: melting_point
    label: Solidus and liquidus, phosphor bronze C52100
    value: 882
    value_high: 1027
    bound: range
    unit: °C
    scope: material
    conditions:
      grade: C52100
      unit_in_source: solidus 1620 °F; liquidus 1880 °F
      pressure: not stated
    method: Solidus and liquidus printed in the physical properties table of a manufacturer page; value is the solidus (low) and the liquidus (high)
    status: ground
    note: The Aurubis datasheet prints a single melting point of 1040 °C (1904 °F) for the same alloy. The Concast range is used here and the conflict is listed in gaps.
    source: concast-c52100
    where: Physical properties table, rows Melting range liquidus and solidus
  - benchmark: electrical_conductivity
    label: Electrical conductivity, phosphor bronze C52100
    value: 13
    unit: '%IACS'
    scope: material
    conditions:
      grade: C52100
      temperature: 68 °F (20 °C)
      unit_in_source: 13% IACS at 68 °F
    method: Value printed in the physical properties table of a manufacturer page
    status: ground
    source: concast-c52100
    where: Physical properties table, row Electrical conductivity
  - benchmark: thermal_conductivity
    label: Thermal conductivity at 20 °C, phosphor bronze C52100
    value: 67
    unit: W/(m·K)
    scope: material
    conditions:
      temperature: 20 °C
      unit_in_source: 39 Btu/ft h °F
    method: Value printed in a manufacturer technical datasheet
    status: ground
    note: The Concast table prints 36 Btu/sq ft/ft hr/°F (62.3 W/m) for the same alloy. The Aurubis value is used and the conflict is listed in gaps.
    source: aurubis-c52100
    where: Physical properties table, row Thermal cond. at 20 °C, metric value
  - benchmark: cte
    label: Coefficient of linear thermal expansion, 20 to 300 °C
    value: 17.4
    unit: µm/(m·°C)
    scope: material
    conditions:
      temperature_range: 20 to 300 °C
      unit_in_source: 10.1 ·10-6 per °F (68-572 °F)
    method: Value printed in a manufacturer page, physical properties table
    status: ground
    source: concast-c52100
    where: Physical properties table, row CTE, metric value
  - benchmark: specific_heat
    label: Specific heat capacity at 20 °C, phosphor bronze C52100
    value: 0.377
    unit: kJ/(kg·K)
    scope: material
    conditions:
      temperature: 20 °C
      unit_in_source: 0.09 Btu/lb °F
    method: Value printed in a manufacturer technical datasheet
    status: ground
    source: aurubis-c52100
    where: Physical properties table, row Specific heat capacity at 20 °C, metric value
  - benchmark: elastic_modulus
    label: Modulus of elasticity, phosphor bronze C52100
    value: 115
    unit: GPa
    scope: material
    conditions:
      temperature: 20 °C
      unit_in_source: 16.7 x1000 ksi
    method: Value printed in a manufacturer technical datasheet
    status: ground
    note: The Concast page prints 110310 MPa for the modulus of elasticity in tension. The Aurubis value is used and the difference is listed in gaps.
    source: aurubis-c52100
    where: Physical properties table, row Mod. of elasticity, metric value
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, H02 temper, range
    value: 475
    value_high: 580
    bound: range
    unit: MPa
    scope: material
    conditions:
      temper: H02 (1/2H)
      unit_in_source: 69 to 84 ksi
    method: Range printed in a manufacturer mechanical properties table
    status: ground
    source: aurubis-c52100
    where: Mechanical properties table, row H02 (1/2H), column Rm, metric value
  - benchmark: yield_strength
    label: Yield strength Rp0.2, H02 temper, minimum
    value: 350
    bound: lower
    unit: MPa
    scope: material
    conditions:
      temper: H02 (1/2H)
      unit_in_source: 51 ksi
    method: Minimum value printed in a manufacturer mechanical properties table
    status: ground
    source: aurubis-c52100
    where: Mechanical properties table, row H02 (1/2H), column Rp0.2 min, metric value
  - benchmark: elongation
    label: Elongation, H02 temper, minimum
    value: 25
    bound: lower
    unit: '%'
    scope: material
    conditions:
      temper: H02 (1/2H)
      gauge_length: 2 inch
    method: Minimum value printed in a manufacturer mechanical properties table
    status: ground
    source: aurubis-c52100
    where: Mechanical properties table, row H02 (1/2H), column Elongation 2 inch
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, H04 hard temper, minimum
    value: 585
    bound: lower
    unit: MPa
    scope: material
    conditions:
      temper: H04 hard
      size: 1/4 to 1/2 inch round and hexagonal
      unit_in_source: 85 ksi
      standard: ASTM B139/B139M
    method: Minimum value printed in a manufacturer mechanical properties table
    status: ground
    source: concast-c52100
    where: Mechanical properties table, row 1/4 to 1/2 inch inclusive, column Tensile strength min
  - benchmark: elongation
    label: Elongation, H04 hard temper, minimum
    value: 12
    bound: lower
    unit: '%'
    scope: material
    conditions:
      temper: H04 hard
      size: 1/4 to 1/2 inch round and hexagonal
      basis: 4 times diameter
    method: Minimum value printed in a manufacturer mechanical properties table
    status: ground
    source: concast-c52100
    where: Mechanical properties table, row 1/4 to 1/2 inch inclusive, column Elongation min
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, H08 spring temper, range
    value: 725
    value_high: 820
    bound: range
    unit: MPa
    scope: material
    conditions:
      temper: H08 (SH) spring
      unit_in_source: 105 to 119 ksi
    method: Range printed in a manufacturer mechanical properties table
    status: ground
    source: aurubis-c52100
    where: Mechanical properties table, row H08 (SH), column Rm, metric value
  - benchmark: yield_strength
    label: Yield strength Rp0.2, H08 spring temper, minimum
    value: 690
    bound: lower
    unit: MPa
    scope: material
    conditions:
      temper: H08 (SH) spring
      unit_in_source: 100 ksi
    method: Minimum value printed in a manufacturer mechanical properties table
    status: ground
    source: aurubis-c52100
    where: Mechanical properties table, row H08 (SH), column Rp0.2 min, metric value
  - benchmark: elongation
    label: Elongation, H08 spring temper, minimum
    value: 3
    bound: lower
    unit: '%'
    scope: material
    conditions:
      temper: H08 (SH) spring
      gauge_length: 2 inch
    method: Minimum value printed in a manufacturer mechanical properties table
    status: ground
    source: aurubis-c52100
    where: Mechanical properties table, row H08 (SH), column Elongation 2 inch
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, H10 extra spring temper, range
    value: 760
    value_high: 840
    bound: range
    unit: MPa
    scope: material
    conditions:
      temper: H10 (ES) extra spring
      unit_in_source: 110 to 122 ksi
    method: Range printed in a manufacturer mechanical properties table
    status: ground
    source: aurubis-c52100
    where: Mechanical properties table, row H10 (ES), column Rm, metric value
  - benchmark: yield_strength
    label: Yield strength Rp0.2, H10 extra spring temper, minimum
    value: 725
    bound: lower
    unit: MPa
    scope: material
    conditions:
      temper: H10 (ES) extra spring
      unit_in_source: 105 ksi
    method: Minimum value printed in a manufacturer mechanical properties table
    status: ground
    source: aurubis-c52100
    where: Mechanical properties table, row H10 (ES), column Rp0.2 min, metric value
  - benchmark: ultimate_tensile_strength
    label: Ultimate tensile strength, hard temper (France et al. 1969 data)
    value: 690
    unit: MPa
    scope: material
    conditions:
      temper: hard
      form: strip
      unit_in_source: 100 ksi
    method: Value in the data file of a University of Waterloo materials page, which cites W.D. France et al., ASTM Journal of Materials, 1969; the source notes the data were digitised from plots and may contain errors
    status: ground
    source: fde-521-hard
    where: Data file header, Su= 690 mpa
  - benchmark: yield_strength
    label: Yield strength, hard temper (France et al. 1969 data)
    value: 510
    unit: MPa
    scope: material
    conditions:
      temper: hard
      form: strip
    method: Value in the data file of a University of Waterloo materials page; digitised from plots
    status: ground
    source: fde-521-hard
    where: Data file header, Sy= 510 mpa
  - benchmark: elongation
    label: Elongation, hard temper (France et al. 1969 data)
    value: 10
    unit: '%'
    scope: material
    conditions:
      temper: hard
      gauge_length: 2 inch
    method: Value in the data file of a University of Waterloo materials page; digitised from plots
    status: ground
    source: fde-521-hard
    where: Data file header, %Elongation= 10 % over 2 inch
corrosion:
  - environment: Seawater and weak acids, manufacturer claim
    headline: The jtcopper page states a seawater corrosion rate below 0.015 mm/year for C52100.
    effect: The page gives this rate in its key features and core advantages sections but names no test method or exposure time. It is recorded as a claim, not a test result.
    rating: low
    conditions:
      basis: manufacturer statement, no test standard named
      exposure: seawater, duration not stated
    source: jtcopper-c52100
    where: Key Features and Core Advantages sections, seawater corrosion rate line
  - environment: Air and general service, qualitative
    headline: Aurubis rates C52100 as having better corrosion resistance than the other alloys in its family and good sliding properties, with no numeric rate.
    effect: The datasheet text says the alloy has better corrosion resistance, and it names no exposure or test. No corrosion rate in mm/year or mpy was printed on any page read in this run.
    rating: low
    conditions:
      basis: qualitative statement from a manufacturer datasheet
      exposure: not stated
    source: aurubis-c52100
    where: Description paragraph
  - environment: Alloy chemistry, tin content
    headline: Tin is the element that gives phosphor bronze its corrosion resistance and strength.
    effect: Wikipedia says tin increases the corrosion resistance and strength of the alloy. The article gives no corrosion data and describes phosphor bronze in general, not C52100 in particular.
    rating: low
    conditions:
      basis: general description, no test data
    source: wikipedia-phosphor-bronze
    where: Introduction, lead paragraph
risks:
  hazards:
    - text: The Fisk Alloy SDS lists C52100 in its product identifier and classifies the solid alloy as Not Classified under GHS-US, with No Labeling Applicable. Cutting, welding, melting or grinding produce dust and fume that may cause irritation and metal fume fever, and fine dust in air may present an explosion hazard.
      ghs: []
      source: fisk-sds
      where: Section 2, Hazard(s) identification (classification table and HNOC paragraphs)
    - text: The same SDS says tin dust and fume may cause stannosis after chronic exposure, that tin has been shown to increase sarcoma incidence in animal tests, and that long-term phosphorus exposure may affect the kidney and liver.
      ghs: []
      source: fisk-sds
      where: Section 11, Toxicological information, tin and phosphorus paragraphs
  failure_risks:
    - mode: Fatigue under reversed bending
      trigger: Cyclic bending of hard temper strip at stress amplitudes of about 187 to 329 MPa
      consequence: In the digitised 1969 data, the sample at 329 MPa failed at 830,340 reversals, and the samples at 187 and 194 MPa reached 200,000,000 reversals without failure.
      severity: moderate
      source: fde-521-hard
      where: Data file table, rows with StsAmpl 329 and runout rows at 187 and 194
    - mode: Exceeding the maximum service temperature
      trigger: Service above 200 °C
      consequence: The jtcopper page prints a maximum service temperature of 200 °C. Above it the spring temper and its strength are not expected to hold, but the page gives no test basis for the limit.
      severity: moderate
      source: jtcopper-c52100
      where: Physical properties table, row Max Service Temp
  side_effects: []
  handling:
    - text: Specify the temper, since H02, H04, H08 and H10 have very different strengths, from 475 to 580 MPa for H02 to 725 to 820 MPa for H08.
      source: aurubis-c52100
      where: Mechanical properties table, all tempers
    - text: H04 hard has a minimum tensile strength of 585 MPa in 1/4 to 1/2 inch round and hexagonal sizes.
      source: concast-c52100
      where: Mechanical properties table, H04 row
    - text: Control dust, fume and sparks when cutting, grinding or welding, since the SDS warns of irritation and a combustible dust hazard.
      source: fisk-sds
      where: Section 2, Hazard(s) identification
  mitigations: []
uses:
  - application: electronics-and-chips
    device: Connectors and relay springs
    example: Aurubis lists connectors, frame connectors, relays and conductor springs among the typical uses of C52100, in automotive and electrical engineering components.
    source: aurubis-c52100
    where: Typical uses section
  - application: mechanisms
    device: Springs, slide bearings and bushings
    example: Aurubis lists spring rings and slide bearings and bushings among the typical uses of C52100. Wikipedia lists springs, bolts, bushings, bearings and electrical switches with moving or sliding parts among phosphor bronze uses.
    source: aurubis-c52100
    where: Typical uses section, spring rings, slide bearings and bushings
  - application: structures
    device: Retaining clamps
    example: Aurubis lists retaining clamps among the typical uses of C52100.
    source: aurubis-c52100
    where: Typical uses section, retaining clamps
supply:
  - subject: Copper (remainder of the alloy)
    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, 90 FR 50494)
        listed: true
    recycling: 'USGS: old scrap provided an estimated 160,000 tons of copper in 2025, and about 760,000 tons was recovered from new scrap; scrap contributed about 30 % of U.S. copper supply.'
    substitutes:
      - 'USGS: aluminum substitutes for copper in electrical equipment and power cable, and optical fiber substitutes for copper in telecommunications applications.'
    source: usgs-mcs2026-copper
    where: World Mine and Refinery Production and Reserves table, mine production 2025e (world total 23,000; Chile 5,300; Congo (Kinshasa) 3,200; Peru 2,700; China 1,800; Russia 1,300); shares calculated from those values; Critical minerals text; Recycling; Substitutes
  - subject: Tin (7.00 to 9.00 % of the alloy)
    producers:
      - country: China
        share_percent: 24.5
        year: 2025
      - country: Indonesia
        share_percent: 21
        year: 2025
      - country: Peru
        share_percent: 11.4
        year: 2025
      - country: Brazil
        share_percent: 9.7
        year: 2025
      - country: Congo (Kinshasa)
        share_percent: 9.3
        year: 2025
    critical_lists: []
    recycling: 'USGS: about 17,000 tons of tin from old and new scrap was estimated to have been recycled in 2025.'
    substitutes:
      - 'USGS: aluminum, glass, paper, plastic or tin-free steel substitute for tin in cans and containers; epoxy resins substitute for tin in solder.'
    source: usgs-mcs2026-tin
    where: World Mine Production and Reserves table, mine production 2025e (world total 290,000; China 71,000; Indonesia 61,000; Peru 33,000; Brazil 28,000; Congo (Kinshasa) 27,000); shares calculated from those values; Recycling; Substitutes
documents:
  - title: Aurubis, Technical Datasheet C52100 (CuSn8), 18 08 US
    type: datasheet
    url: https://www.aurubis.be/en/dam/jcr:c9afaa1f-9929-4944-9580-207b545952b6/c52100-cusn8-us.pdf
  - title: Concast, C52100 phosphor bronze product page (composition, physical, mechanical and designation tables)
    type: datasheet
    url: https://concast.com/c52100.php
  - title: jtcopper, C52100 bronze product page
    type: datasheet
    url: https://en.jtcopper.com/c52100-bronze.html
  - title: University of Waterloo FDE data file, Phosphor bronze 8 % Sn hard temper (after W.D. France et al., ASTM Journal of Materials, 1969)
    type: database
    url: https://fde.uwaterloo.ca/Fde/Materials/Other/France/france-PhosphorBronze521-hard.html
  - title: 'Wikipedia: Phosphor bronze'
    type: database
    url: https://en.wikipedia.org/wiki/Phosphor_bronze
  - title: Fisk Alloy Safety Data Sheet FAWSDS-5, C51000, C51900, C52100 (revision 11-09-2017)
    type: sds
    url: https://fiskalloy.com/wp-content/uploads/2023/11/Fisk-Alloy-Safety-Datasheet-FAWSDS-5.pdf
    year: 2017
  - 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: Tin'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-tin.pdf
    year: 2026
gaps:
  - 'Critical name conflict: the Concast page prints CW451K for C521, but the Aurubis datasheet prints CW453K for C52100. CW453K is entered. The sister profile bronze-c510 uses CW451K for C51000, so the EN code is not resolved here.'
  - 'Melting point conflict: Concast prints solidus 882 °C and liquidus 1027 °C; Aurubis prints a single melting point of 1040 °C (1904 °F). The Concast range is used.'
  - 'Thermal conductivity conflict: Concast prints 36 Btu/sq ft/ft hr/°F (62.3 W/m); Aurubis prints 39 Btu/ft h °F (67 W/mK). The Aurubis value is used.'
  - 'Modulus conflict: Concast prints 110310 MPa; Aurubis prints 115 GPa. The Aurubis value is used.'
  - 'Electrical conductivity: Aurubis prints 12.9 %IACS for the soft condition only, and Concast prints 13 %IACS at 68 °F. The Concast value is used.'
  - The jtcopper page prints tensile strengths for H08 (860 to 1035 MPa) and H02 (655 to 795 MPa) that do not match the Aurubis table (725 to 820 MPa and 475 to 580 MPa). The page says its data were synthesized from ASTM, GB, JIS and manufacturer specifications, so its tensile and hardness values are not entered. Only its seawater corrosion claim and max service temperature are used, and both are flagged as claims.
  - The Concast table lists only one temper (H04) for ASTM B139. The spring tempers rest on one manufacturer datasheet (Aurubis), so they need a mill certificate check before design use.
  - The aircraftmaterials.com CDA 521 page returned HTTP 404 and was not used. The Concast PDF was not retrieved in this run.
  - The FDE 1969 values are digitised from plots and come from one source. The FDE page title reads Alloy-C521000, a typo for C52100, and it prints the modulus with no unit, so the modulus is not entered from it.
  - No annealing or stress-relief temperature range for C52100 was found in the sources read, so the loss-of-temper failure route is not entered.
  - Hardness (Rockwell B 93 typical for H04, Concast) is printed but not entered, because its name is not in the canonical property list.
  - The seawater corrosion rate below 0.015 mm/year is an unnamed-test manufacturer claim, not a test result read from a standard.
  - Atomic weights for the alloy elements were not found in the sources, so the recipe parts carry weight shares only.
  - The USGS tin summary read in this run does not mention a critical minerals list, so the critical list field for tin is empty.
  - Outgassing, cold welding and atomic oxygen erosion for C52100 were not searched and no values are recorded.
  - The W.Nr. number was not printed on any fetched page and is not entered. The UE9P, DTD265A and CW451K designations printed on the Concast page are not entered as the EN or AFNOR grade codes, because the other sources conflict or do not print them for C52100.
sources:
  aurubis-c52100:
    title: Aurubis, Technical Datasheet C52100 (CuSn8), 18 08 US
    url: https://www.aurubis.be/en/dam/jcr:c9afaa1f-9929-4944-9580-207b545952b6/c52100-cusn8-us.pdf
    kind: datasheet
    license: Manufacturer datasheet (cited, not reproduced)
  concast-c52100:
    title: Concast, C52100 phosphor bronze product page
    url: https://concast.com/c52100.php
    kind: datasheet
    license: Manufacturer product page (cited, not reproduced)
  jtcopper-c52100:
    title: jtcopper, C52100 bronze product page
    url: https://en.jtcopper.com/c52100-bronze.html
    kind: datasheet
    license: Supplier page (cited, not reproduced)
  fde-521-hard:
    title: University of Waterloo FDE, Phosphor bronze 8 % Sn hard temper, from W.D. France et al., ASTM Journal of Materials, 1969
    url: https://fde.uwaterloo.ca/Fde/Materials/Other/France/france-PhosphorBronze521-hard.html
    kind: database
    license: University web page (cited, not reproduced)
  wikipedia-phosphor-bronze:
    title: 'Wikipedia: Phosphor bronze'
    url: https://en.wikipedia.org/wiki/Phosphor_bronze
    kind: web
    license: CC BY-SA 4.0 (cited, not reproduced)
  fisk-sds:
    title: Fisk Alloy Safety Data Sheet FAWSDS-5, C51000, C51900, C52100
    url: https://fiskalloy.com/wp-content/uploads/2023/11/Fisk-Alloy-Safety-Datasheet-FAWSDS-5.pdf
    year: 2017
    kind: datasheet
    license: Manufacturer safety data sheet (cited, not reproduced)
  usgs-mcs2026-copper:
    title: Mineral Commodity Summaries 2026, Copper
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-copper.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  usgs-mcs2026-tin:
    title: Mineral Commodity Summaries 2026, Tin
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-tin.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: 20
  unreachable: 2
  caveats: 6
  note: 'Values were read by an AI assistant on 2026-10-26 from the pages and PDFs named in each entry; the USGS PDFs were extracted with pdftotext and the Aurubis datasheet with pdftotext -layout. Unreachable: the aircraftmaterials.com CDA 521 page (HTTP 404) and the Concast PDF (not retrieved). Caveats: the FDE values are digitised from plots; the melting, thermal conductivity and modulus figures conflict between Concast and Aurubis; the spring tempers rest on a single datasheet; the jtcopper tensile values conflict with the other sources and are not used; the EN code CW451K versus CW453K is unresolved.'
story:
  risk_groups:
    - title: For people
      lead: The opened sources give a hazard for dust and fume from the alloy, not for the solid metal.
      level: 1
      verdict: Dust and fume, not solid metal
      points:
        - label: Solid alloy
          line: The Fisk SDS classifies the solid alloy as Not Classified under GHS-US, with no labelling. Hazards come from the dust, fume and powder made when it is cut, ground or welded.
        - label: Tin and phosphorus in dust
          line: The same SDS says tin dust and fume can cause stannosis after chronic exposure and that tin has been shown to increase sarcoma incidence in animal tests. It also says long-term phosphorus exposure may affect the kidney and liver.
    - title: If it fails
      lead: The failure routes in the sources are fatigue in hard temper strip and use above the printed service limit.
      points:
        - label: Fatigue
          line: In the digitised 1969 data, a sample at 329 MPa stress amplitude failed at 830,340 reversals, and samples at 187 and 194 MPa reached 200,000,000 reversals without failure.
        - label: Service limit
          line: The jtcopper page prints a maximum service temperature of 200 °C. It gives no test basis for that figure.
    - title: Handling and storage
      points:
        - label: Specify the temper
          line: H02 has 475 to 580 MPa tensile strength, H08 spring has 725 to 820 MPa, and H10 extra spring has 760 to 840 MPa. Choose the temper before the strength is quoted.
        - label: Dust
          line: Control dust, fume and sparks when cutting, grinding or welding.
  why: Phosphor bronze C52100 is a copper alloy with about 8 % tin and 0.2 % phosphorus. Aurubis calls it the highest alloyed phosphor bronze in its family, and the tin gives it high strength with still adequate conductivity. The Aurubis table gives 725 to 820 MPa tensile for the H08 spring temper, and Concast gives 585 MPa minimum for H04 hard. The alloy is used for springs, connectors, relays and slide bearings.
  uses:
    - where: Connectors and relays
      line: Aurubis lists connectors, frame connectors, relays and conductor springs among the typical uses of C52100.
    - where: Springs and slide bearings
      line: Aurubis lists spring rings, slide bearings and bushings. Wikipedia lists springs, bolts, bushings and bearings among phosphor bronze uses.
    - where: Retaining clamps
      line: Aurubis lists retaining clamps among the typical uses of C52100.
  can_do:
    - label: Carry springs
      value: 725 to 820 MPa tensile
      benchmark: ultimate_tensile_strength
      line: The H08 spring temper has a tensile range of 725 to 820 MPa, with a minimum yield of 690 MPa (Aurubis).
    - label: Take the density
      value: 8.79 g/cm3
      benchmark: density
      line: The Aurubis datasheet gives a density of 8.79 g/cm3 at 20 °C.
    - label: Conduct electricity
      value: 13 %IACS
      benchmark: electrical_conductivity
      line: The Concast page gives an electrical conductivity of 13 %IACS at 68 °F.
    - label: Melt
      value: 882 to 1027 °C
      benchmark: melting_point
      line: The solidus is 882 °C and the liquidus is 1027 °C in the Concast table. The Aurubis datasheet gives a single melting point of 1040 °C.
  compare: Among the phosphor bronzes, C52100 is the highest-tin member (7.00 to 9.00 % tin in the ASTM B139 limits). Its strength in the spring tempers is the highest of the tin-bronze grades read here, and its electrical conductivity is 13 %IACS. The lower-tin C51000 grade has its own profile, bronze-c510, for direct comparison.
  compare_rows:
    - label: Density
      benchmark: density
    - label: Electrical conductivity
      benchmark: electrical_conductivity
    - label: Thermal expansion
      benchmark: cte
  handling:
    - Specify the temper, since the strength depends strongly on it.
    - 'Solder and braze the alloy: the Aurubis fabrication table rates soldering and brazing as excellent.'
    - Control dust, fume and sparks when cutting, grinding or welding.
  good_for:
    - 'Springs and connectors: the H08 spring temper gives 725 to 820 MPa tensile strength, with 690 MPa minimum yield (Aurubis).'
    - 'Slide bearings and bushings: Aurubis rates the alloy for good sliding properties and wear resistance.'
    - 'Solderable and brazeable parts: Aurubis rates soldering and brazing as excellent.'
  watch_out:
    - Dust and fume when cut, ground or welded, per the Fisk SDS.
    - Spring tempers rest on one manufacturer datasheet, so confirm the temper on a mill certificate.
    - The seawater corrosion rate below 0.015 mm/year is a manufacturer claim without a named test.
    - Melting, thermal conductivity and modulus figures differ between the Concast and Aurubis sources.
  verdict: Phosphor bronze C52100 is the highest-tin member of the phosphor bronze family, with 7.00 to 9.00 % tin. Its strength depends strongly on temper, and the H08 spring temper gives 725 to 820 MPa tensile strength. The alloy solders and brazes well, and dust from machining is the main hazard. This profile lacks a verified seawater test, a confirmed EN code and an annealing range.
  recipe:
    line: 'C52100 is a copper-tin-phosphorus alloy: copper is the matrix, and tin gives most of the strength and the corrosion resistance. Phosphorus is a trace addition that Wikipedia says raises wear resistance and stiffness. Lead, zinc and iron are impurity limits, and the wrought bar, rod, wire and strip are made by cold working and annealing.'
    parts:
      - name: Copper
        symbol: Cu
        share: remainder
        role: The matrix. Concast and the ASTM B139 composition table give copper as the remainder.
      - name: Tin
        symbol: Sn
        share: 7.00 to 9.00 %
        role: Gives most of the strength and corrosion resistance (Concast composition table, Wikipedia).
      - name: Phosphorus
        symbol: P
        share: 0.03 to 0.35 %
        role: A trace addition that raises wear resistance and stiffness (Wikipedia).
      - name: Lead
        symbol: Pb
        share: 0.05 % max
        role: Impurity limit.
      - name: Zinc
        symbol: Zn
        share: 0.20 % max
        role: Impurity limit.
      - name: Iron
        symbol: Fe
        share: 0.10 % max
        role: Impurity limit.
