spore: profile
id: silver-steel
spore_version: 0.2
family: tool-steels
name: Silver steel (BS 1407 high-carbon bright tool steel)
abbreviation: BS 1407
role: precision-ground tool steel bar
category: metals
type: steels-and-stainless
summary: |
  Silver steel is a high-carbon, chromium-bearing tool steel made to British Standard BS 1407 and sold as precision ground bar. The certificate of conformity sets carbon at 0.95 to 1.25 % and chromium at 0.35 to 0.45 %, and the bar as delivered is no harder than 285 HB. The European equivalent 1.2210 (115CrV3) hardens to 64 to 66 HRC by quenching, but the steel is not corrosion resistant and rusts unless protected.
best_for: Hardened precision pins, punches, shafts and small tooling where bright ground bar and a hardness of 64 to 66 HRC after quenching are needed (1.2210 datasheet)
weakest_at: 'Corrosion resistance: the 1.2210 datasheet says the steel is not corrosion resistant and will rust unless protected. It also softens on tempering, from 62 HRC at 200 °C to 51 HRC at 400 °C.'
identity:
  formula: 'Iron-based high-carbon steel: C 0.95 to 1.25 %, Cr 0.35 to 0.45 %, Mn 0.25 to 0.45 %, Si 0.4 % maximum, P 0.045 % maximum, S 0.045 % maximum, balance Fe (BS 1407 analysis range, weight percent)'
  source: protool-cert
  where: Analysis Range % table on the certificate of conformity, and the opening paragraph that names BS 1407
  designations:
    - system: BS
      code: '1407'
      source: protool-cert
      where: Opening paragraph ('British Standard Specification Number BS 1407')
    - system: EN
      code: '1.2210'
      source: wikipedia-silver-steel
      where: Composition section ('The European/Werkstoff equivalent is 1.2210 / 115CrV3')
    - system: DIN
      code: 115CrV3
      source: wikipedia-silver-steel
      where: Composition section ('The European/Werkstoff equivalent is 1.2210 / 115CrV3')
    - system: AISI
      code: L2
      note: printed on the 1.2210 page, which headers the grade as Silver Steel
      source: abrams-1-2210
      where: Grade header, 'AISI/SAE L2; T61202'
    - system: UNS
      code: T61202
      note: printed on the 1.2210 page against AISI/SAE L2
      source: abrams-1-2210
      where: Grade header, 'AISI/SAE L2; T61202'
    - system: JIS
      code: SKS43
      source: terasrenki-2210
      where: Material Code table, JIS column (1.2210 115CrV3 datasheet)
tags:
  environments: []
  stresses: []
  applications:
    - mechanisms
properties:
  - benchmark: carbon_content
    label: Carbon, BS 1407 analysis range
    value: 0.95
    value_high: 1.25
    bound: range
    unit: '%'
    scope: material
    conditions:
      basis: analysis range in weight percent, as printed on the certificate
      standard: BS 1407 (optional standard named on the certificate)
    method: Analysis range printed on a manufacturer certificate of conformity
    status: ground
    source: protool-cert
    where: Analysis Range % table (Carbon 0.95/1.25)
  - benchmark: chromium_content
    label: Chromium, BS 1407 analysis range
    value: 0.35
    value_high: 0.45
    bound: range
    unit: '%'
    scope: material
    conditions:
      basis: analysis range in weight percent, as printed on the certificate
      standard: BS 1407
    method: Analysis range printed on a manufacturer certificate of conformity
    status: ground
    source: protool-cert
    where: Analysis Range % table (Chromium 0.35/0.45)
  - benchmark: manganese_content
    label: Manganese, BS 1407 analysis range
    value: 0.25
    value_high: 0.45
    bound: range
    unit: '%'
    scope: material
    conditions:
      basis: analysis range in weight percent, as printed on the certificate
      standard: BS 1407
    method: Analysis range printed on a manufacturer certificate of conformity
    status: ground
    source: protool-cert
    where: Analysis Range % table (Manganese 0.25/0.45)
  - benchmark: silicon_content
    label: Silicon, BS 1407 analysis maximum
    value: 0.4
    bound: upper
    unit: '%'
    scope: material
    conditions:
      basis: analysis maximum in weight percent, as printed on the certificate
      standard: BS 1407
    method: Analysis maximum printed on a manufacturer certificate of conformity
    status: ground
    source: protool-cert
    where: Analysis Range % table (Silicon 0.4 max)
  - benchmark: phosphorus_content
    label: Phosphorus, BS 1407 analysis maximum
    value: 0.045
    bound: upper
    unit: '%'
    scope: material
    conditions:
      basis: analysis maximum in weight percent, as printed on the certificate
      standard: BS 1407
    method: Analysis maximum printed on a manufacturer certificate of conformity
    status: ground
    source: protool-cert
    where: Analysis Range % table (Phosphorus 0.045 max)
  - benchmark: sulphur_content
    label: Sulphur, BS 1407 analysis maximum
    value: 0.045
    bound: upper
    unit: '%'
    scope: material
    conditions:
      basis: analysis maximum in weight percent, as printed on the certificate
      standard: BS 1407
    method: Analysis maximum printed on a manufacturer certificate of conformity
    status: ground
    source: protool-cert
    where: Analysis Range % table (Sulphur 0.045 max)
  - benchmark: hardness_brinell
    label: Hardness as delivered, typical range (spheroidised and annealed)
    value: 207
    value_high: 235
    bound: range
    unit: HB
    scope: material
    conditions:
      condition: spheroidised and annealed, as delivered
      basis: typical range printed on the certificate, not a guaranteed limit
    method: Typical range printed on a manufacturer certificate of conformity
    status: ground
    source: protool-cert
    where: Opening paragraph ('typical hardness of 207-235HB with 285HB maximum')
  - benchmark: hardness_brinell
    label: Maximum hardness as delivered
    value: 285
    bound: upper
    unit: HB
    scope: material
    conditions:
      condition: as delivered, measured to BS 240 as the supplier states
    method: Maximum printed on the manufacturer's product page
    status: ground
    source: tas-product
    where: Product description, paragraph 1 ('not more than 285HB when measured in accordance with BS240')
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, annealed (45/55 TPSI)
    value: 700
    value_high: 850
    bound: range
    unit: N/mm2
    scope: material
    conditions:
      condition: annealed, as supplied
      printed_in_source: 45/55 TPSI
    method: Range printed on a manufacturer certificate of conformity
    status: ground
    source: protool-cert
    where: Tensile strength line ('45/55 TPSI (700/850 N/mm2)')
  - benchmark: hardness_rockwell_c
    label: Hardness after quenching, 1.2210 datasheet
    value: 64
    value_high: 66
    bound: range
    unit: HRC
    scope: material
    conditions:
      grade: 1.2210 (SIHARD 2210, 115CrV3); the European equivalent that Wikipedia names. Its chromium and vanadium contents differ from the BS 1407 analysis.
      quench: water or oil, as printed
    method: Range printed in a steel-maker's datasheet
    status: ground
    source: ravne-2210
    where: Hardening section ('Hardness after quenching is 64-66, 64-66 HRC')
  - benchmark: hardness_rockwell_c
    label: Maximum working hardness, 1.2210 datasheet
    value: 62
    bound: upper
    unit: HRC
    scope: material
    conditions:
      grade: 1.2210 (115CrV3); the European equivalent named by Wikipedia
    method: Maximum printed in a manufacturer datasheet
    status: ground
    source: abrams-1-2210
    where: Physical properties ('Working hardness max. 62 HRC')
  - benchmark: hardness_rockwell_c
    label: Hardness after tempering at 200 °C, 1.2210 datasheet
    value: 62
    unit: HRC
    scope: material
    conditions:
      grade: 1.2210 (115CrV3)
      tempering_temperature: 200 °C
    method: Value in the tempering table of a manufacturer datasheet
    status: ground
    source: abrams-1-2210
    where: Heat treatment, Tempering row, 200°C column
  - benchmark: hardness_rockwell_c
    label: Hardness after tempering at 400 °C, 1.2210 datasheet
    value: 51
    unit: HRC
    scope: material
    conditions:
      grade: 1.2210 (115CrV3)
      tempering_temperature: 400 °C
    method: Value in the tempering table of a manufacturer datasheet
    status: ground
    source: abrams-1-2210
    where: Heat treatment, Tempering row, 400°C column
  - benchmark: density
    label: Density, 1.2210 datasheet average value
    value: 7.8
    unit: g/cm3
    scope: material
    conditions:
      grade: 1.2210 (SIHARD 2210)
      temperature: ambient, as the datasheet heading says
    method: Average value printed in a steel-maker's datasheet
    status: ground
    source: ravne-2210
    where: Physical properties (average values) at ambient temperature, Density row
  - benchmark: thermal_conductivity
    label: Thermal conductivity, 1.2210 datasheet average value
    value: 33.5
    unit: W/m.K
    scope: material
    conditions:
      grade: 1.2210 (SIHARD 2210)
      temperature: ambient, as the datasheet heading says
    method: Average value printed in a steel-maker's datasheet
    status: ground
    source: ravne-2210
    where: Physical properties (average values) at ambient temperature, Thermal conductivity row (first value)
  - benchmark: cte
    label: Coefficient of linear thermal expansion, 1.2210, 20 to 100 °C
    value: 11.8
    unit: ppm/K
    scope: material
    conditions:
      grade: 1.2210 (SIHARD 2210)
      temperature_range: 20 to 100 °C
      unit_in_source: 10-6 oC-1 (equal to ppm/K)
    method: Value printed in a steel-maker's datasheet
    status: ground
    source: ravne-2210
    where: Coefficient of Linear Thermal Expansion table, 20-100 oC column
  - benchmark: hardening_temperature
    label: Hardening temperature, 1.2210 datasheet
    value: 780
    value_high: 820
    bound: range
    unit: °C
    scope: material
    conditions:
      grade: 1.2210 (SIHARD 2210)
      quench: water or oil quench, as printed
    method: Range printed in a steel-maker's datasheet
    status: ground
    source: ravne-2210
    where: Hardening section ('Harden from a temperature of 780-820oC')
  - benchmark: hardening_temperature
    label: Hardening temperature, BS 1407 silver steel (manufacturer specification)
    value: 760
    value_high: 800
    bound: range
    unit: °C
    scope: material
    conditions:
      basis: heat slowly, then quench into well agitated water, as printed
    method: Range printed on the manufacturer's technical specification (PDF without a text layer, read from the page image)
    status: ground
    source: tas-spec
    where: Heat Treatment, Hardening paragraph ('Heat slowly to 760-800°C')
  - benchmark: hardness_rockwell_c
    label: Approximate quench hardness, BS 1407 silver steel
    value: 65
    value_high: 68
    bound: range
    unit: Rc
    scope: material
    conditions:
      basis: approximate quench hardness, as printed; the scale is printed as Rc
    method: Range printed on the manufacturer's technical specification (PDF without a text layer, read from the page image)
    status: ground
    source: tas-spec
    where: Heat Treatment, Hardening paragraph ('approximate quench hardness is 65 to 68 Rc')
  - benchmark: stress_relief_temperature
    label: Stress-relief temperature, 1.2210 datasheet
    value: 650
    unit: °C
    scope: material
    conditions:
      grade: 1.2210 (SIHARD 2210)
      hold: 1 to 2 hours, then air cooling, as printed
    method: Value printed in a steel-maker's datasheet
    status: ground
    source: ravne-2210
    where: Stress Relieving section ('approx. 650 oC, holding for 1-2 hours')
corrosion:
  - environment: Ordinary air and handling without protection
    headline: The 1.2210 datasheet says this steel is not corrosion resistant and will rust unless protected.
    effect: 'The Ravne datasheet for SIHARD 2210 (1.2210) states: ''This is an alloy steel and it is not corrosion resistant. It will rust unless protected.'' The sheet gives no corrosion rate, humidity exposure or test.'
    rating: moderate
    conditions:
      basis: qualitative statement in the Corrosion Resistance section of the 1.2210 datasheet
      grade: 1.2210 (SIHARD 2210)
      rating_basis: rating assigned by Space Mushroom from the qualitative statement; the datasheet gives no rating
    source: ravne-2210
    where: Corrosion Resistance section
risks:
  hazards:
    - text: 'Solid steel: the grouped safety data sheet for carbon, alloy and tool steels (AISI grades) states that they present no inhalation, ingestion or contact health hazard in their solid state. The sheet does not name silver steel or BS 1407.'
      ghs: []
      source: uwo-sds-steels
      where: Section 4.2 (Overview); Section 1.1 (Product identity and alternate names)
    - text: Dusts and fumes from burning, melting, welding, sawing, brazing, grinding and machining may be hazardous. Excessive exposure can irritate the eyes, nose and throat, and inhaling fumes can cause metal fume fever.
      ghs: []
      source: uwo-sds-steels
      where: Section 4.2 (Overview, acute effects)
  failure_risks:
    - mode: Distortion during heat treatment
      trigger: Hardening machined bar without a prior stress relief
      consequence: Stress relieving at about 650 °C is carried out to reduce distortion during heat treatment, according to the 1.2210 datasheet.
      severity: low
      source: ravne-2210
      where: Stress Relieving section
    - mode: Loss of hardness from over-tempering
      trigger: Tempering at 400 °C instead of 200 °C (1.2210 datasheet table)
      consequence: Hardness falls from 62 HRC after tempering at 200 °C to 51 HRC after tempering at 400 °C.
      severity: moderate
      source: abrams-1-2210
      where: Heat treatment, Tempering row
    - mode: Rusting in storage or handling
      trigger: Bare steel left in damp air or handled without protection
      consequence: The 1.2210 datasheet says the steel will rust unless protected.
      severity: moderate
      source: ravne-2210
      where: Corrosion Resistance section
  handling:
    - text: 'Stress relieve after heavy machining: the 1.2210 datasheet gives about 650 °C, held for one to two hours, then air cooling.'
      source: ravne-2210
      where: Stress Relieving section
    - text: Temper after hardening. The 1.2210 tempering table gives 62 HRC at 200 °C and 51 HRC at 400 °C.
      source: abrams-1-2210
      where: Heat treatment, Tempering row
  mitigations:
    - text: Use local exhaust ventilation where grinding, welding or burning makes dust or fume, and wear a NIOSH approved dust, mist or fume respirator when welding or burning this metal.
      source: uwo-sds-steels
      where: Exposure controls and personal protection (respiratory protection); precautionary statement P261
uses:
  - application: mechanisms
    device: Punches, dowels, mandrels, spindles, shafts, guide pins and ejector pins
    example: The supplier lists punches, dowels, mandrels, spindles, drill bushes, shafts, engraving tools, knurls, collets and lathe centres as customer applications for its BS 1407 silver steel.
    source: tas-product
    where: Product description, paragraph 3 (Customer applications)
  - application: mechanisms
    device: 'Hand tools: punches, engravers and screwdrivers'
    example: Wikipedia says silver steel has been widely used to make punches, engravers and screwdrivers.
    source: wikipedia-silver-steel
    where: Uses section
  - application: mechanisms
    device: Drills, broaching tools, engraving tools, ejectors and metal saws (1.2210 equivalent)
    example: The 1.2210 datasheet lists spiral and tap drills, broaching tools, engraving tools, ejectors and metal saws as applications for the grade.
    source: ravne-2210
    where: Applications section
supply:
  - subject: Iron
    producers:
      - country: Australia
        share_percent: 37.7
        year: 2025
      - country: Brazil
        share_percent: 16.2
        year: 2025
      - country: India
        share_percent: 11.9
        year: 2025
      - country: China
        share_percent: 11.2
        year: 2025
    critical_lists:
      - list: USGS 2025 List of Critical Minerals
        listed: false
    recycling: Not stated in the USGS iron ore summary used for this profile.
    substitutes: []
    source: usgs-mcs2026-iron-ore
    where: 'World Mine Production and Reserves table, usable ore, 2025e (world total 2,600,000 thousand t; shares calculated by Space Mushroom from the Australia 980,000, Brazil 420,000, India 310,000 and China 290,000 values). The table is iron ore, the feedstock of the steel''s iron, not steel itself. Critical list: USGS 2025 list page.'
  - subject: Chromium
    producers:
      - country: South Africa
        share_percent: 45.1
        year: 2025
      - country: Turkey
        share_percent: 17.6
        year: 2025
      - country: Kazakhstan
        share_percent: 13.7
        year: 2025
      - country: India
        share_percent: 5.9
        year: 2025
    critical_lists:
      - list: USGS 2025 List of Critical Minerals (listed as used in stainless steel)
        listed: true
    recycling: 'USGS: recycled chromium contained in reported stainless-steel scrap receipts accounted for a share of apparent US consumption in 2025.'
    substitutes:
      - 'USGS: chromium has no substitute in stainless steel or in superalloys; chromium-containing scrap can substitute for ferrochromium in some metallurgical uses.'
    source: usgs-mcs2026-chromium
    where: World Mine Production and Reserves table, 2025e (world total 51,000 thousand t, chromium content; shares calculated by Space Mushroom from the country values); Recycling; Substitutes; critical list from the USGS 2025 list page
  - subject: Manganese
    producers:
      - country: South Africa
        share_percent: 38
        year: 2025
      - country: Gabon
        share_percent: 25
        year: 2025
      - country: Ghana
        share_percent: 10
        year: 2025
      - country: Australia
        share_percent: 8
        year: 2025
    critical_lists:
      - list: USGS 2025 List of Critical Minerals (listed as used in steel production and batteries)
        listed: true
    recycling: 'USGS: manganese was recycled incidentally as a constituent of ferrous and nonferrous scrap.'
    substitutes:
      - 'USGS: manganese has no satisfactory substitute in its major applications.'
    source: usgs-mcs2026-manganese
    where: World Mine Production table, manganese content, 2025e (world total 20,000 thousand t; shares calculated by Space Mushroom from the country values); Recycling; Substitutes; critical list from the USGS 2025 list page
documents:
  - title: T & A Precision Grinding certificate of conformity, Water Hardenable Silver Steel (BS 1407)
    type: datasheet
    url: https://www.protool-ltd.co.uk/cdn/shop/files/silver-steel-information-2.pdf
  - title: 'T & A Precision Silver Steel: BS1407 Technical Specification (PDF without a text layer)'
    type: datasheet
    url: https://www.silver-steel.co.uk/wp-content/uploads/2024/10/BS1407-Technical-Specifications.pdf
    year: 2024
  - title: SIHARD 2210 Steel designation and datasheet (SIJ Metal Ravne, 1.2210)
    type: datasheet
    url: https://steelselector.sij.si/data/pdf/OCR1.pdf
    year: 2016
  - title: ABRAMS PREMIUM 1.2210 (Silver Steel) datasheet
    type: datasheet
    url: https://files.abrams-industries.com/steel/en_eu/1.2210.pdf
    year: 2012
  - title: 1.2210 115CrV3 BS 1407 Silver Steel datasheet (Terasrenki)
    type: datasheet
    url: http://cdna.terasrenki.com/ds/1.2210_115CrV3_BS-1407_SilverSteel_Datasheet_1.pdf
  - title: 'Safety Data Sheet: Carbon, Alloy and Tool Steels AISI Grades (TW Metals, rev. 01/14/2016), copy hosted by University of Western Ontario'
    type: sds
    url: https://www.eng.uwo.ca/files/departments-units/student-shop/2016/sds-carbon-alloy-and-tool-steels.pdf
    year: 2016
  - title: 'USGS Mineral Commodity Summaries 2026: Chromium'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-chromium.pdf
    year: 2026
  - title: 'USGS Mineral Commodity Summaries 2026: Manganese'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-manganese.pdf
    year: 2026
  - title: 'USGS Mineral Commodity Summaries 2026: Iron Ore'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-iron-ore.pdf
    year: 2026
gaps:
  - No yield strength, elongation or fatigue strength for BS 1407 silver steel was found in the sources fetched for this profile.
  - The modulus of elasticity on the 1.2210 datasheet is printed with a multiplier in its unit, so it is left out rather than converted.
  - Density, thermal conductivity, expansion, hardening and tempering rows for the 1.2210 grade come from 1.2210 datasheets. No BS 1407 bar datasheet gave these values. The 1.2210 chromium and vanadium contents are higher than the BS 1407 analysis, so these rows describe the European equivalent, not the BS 1407 bar.
  - The BS 1407 hardening, quench hardness and tempering rows come from a T&A specification PDF with no text layer; they were read from the page image and cannot be matched in text.
  - Wikipedia gives an annealed hardness that does not agree with the certificate's Brinell range, so it is not recorded.
  - The UNS code and AISI L2 come from the Abrams 1.2210 page, which headers the grade as Silver Steel. No UNS code printed for BS 1407 bar itself was found.
  - No corrosion rate, humidity exposure or salt-spray test of silver steel was found. The only corrosion statement is the qualitative sentence on the 1.2210 datasheet.
  - The hazard data rest on a grouped SDS for AISI carbon, alloy and tool steels, not an SDS for silver steel. No toxicology for the bar beyond that statement was found.
  - No side-effect data (outgassing, vacuum or radiation behaviour) and no space-flight use were found; the uses are general precision tooling.
  - Critical-mineral status for chromium and manganese comes from the USGS 2025 list page only; the European Commission critical raw materials list was not checked.
  - Iron recycling is not stated in the USGS iron ore summary used here, so the recycling field is left as a statement of that fact. Carbon supply is not profiled.
  - Supply shares are calculated by Space Mushroom from the USGS production tables, not printed as shares.
  - No image with a verified licence was found, so the profile has no media entry.
  - Packaging and surface finish (lanolin spray, surface finish) appear only in the T&A specification PDF and are not recorded.
sources:
  protool-cert:
    title: Certificate of Conformity, Water Hardenable Silver Steel (T & A Precision Grinding Co., BS 1407)
    id: BS 1407 certificate of conformity, hosted by Protool Ltd
    url: https://www.protool-ltd.co.uk/cdn/shop/files/silver-steel-information-2.pdf
    kind: datasheet
    license: supplier document, linked not reproduced
  tas-spec:
    title: 'T&A Precision Silver Steel: BS1407 Technical Specification'
    id: T & A Precision Grinding Co. Ltd, Commodity Code 7228 5020
    url: https://www.silver-steel.co.uk/wp-content/uploads/2024/10/BS1407-Technical-Specifications.pdf
    year: 2024
    kind: datasheet
    license: supplier document, linked not reproduced
  tas-product:
    title: BS1407 Silver Steel (Metric), T&A Precision Silver Steel product page
    id: silver-steel.co.uk product page
    url: https://www.silver-steel.co.uk/product/bs1407-silver-steel-metric/
    kind: web
    license: supplier web page, linked not reproduced
  wikipedia-silver-steel:
    title: Silver steel (Wikipedia)
    id: Wikipedia article, Silver steel
    url: https://en.wikipedia.org/wiki/Silver_steel
    kind: web
    license: CC BY-SA 4.0 (Wikipedia text; cited, not reproduced)
  ravne-2210:
    title: 'SIHARD 2210 Steel: designation by standards, chemical composition, physical properties and heat treatment (SIJ Metal Ravne)'
    id: SIJ Metal Ravne datasheet, copyright 2016
    url: https://steelselector.sij.si/data/pdf/OCR1.pdf
    year: 2016
    kind: datasheet
    license: manufacturer datasheet, linked not reproduced
  abrams-1-2210:
    title: ABRAMS PREMIUM 1.2210 (Silver Steel), grade datasheet
    id: ABRAMS Industries datasheet, 1.2210 (115CrV3)
    url: https://files.abrams-industries.com/steel/en_eu/1.2210.pdf
    year: 2012
    kind: datasheet
    license: manufacturer datasheet, linked not reproduced
  terasrenki-2210:
    title: 1.2210 115CrV3 BS 1407 Silver Steel datasheet (Terasrenki)
    id: Terasrenki datasheet, 1.2210 115CrV3
    url: http://cdna.terasrenki.com/ds/1.2210_115CrV3_BS-1407_SilverSteel_Datasheet_1.pdf
    kind: datasheet
    license: supplier datasheet, linked not reproduced
  uwo-sds-steels:
    title: 'Safety Data Sheet: Carbon, Alloy and Tool Steels AISI Grades (TW Metals, rev. 01/14/2016)'
    id: TW Metals SDS, copy hosted by University of Western Ontario
    url: https://www.eng.uwo.ca/files/departments-units/student-shop/2016/sds-carbon-alloy-and-tool-steels.pdf
    year: 2016
    kind: datasheet
    license: supplier document, linked not reproduced
  usgs-mcs2026-chromium:
    title: Mineral Commodity Summaries 2026, Chromium
    id: USGS MCS 2026, February 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-chromium.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  usgs-mcs2026-manganese:
    title: Mineral Commodity Summaries 2026, Manganese
    id: USGS MCS 2026, February 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-manganese.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  usgs-mcs2026-iron-ore:
    title: Mineral Commodity Summaries 2026, Iron Ore
    id: USGS MCS 2026, February 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-iron-ore.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  usgs-crit2025:
    title: About the 2025 List of Critical Minerals (USGS)
    id: Final 2025 List of Critical Minerals
    url: https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals
    year: 2025
    kind: web
    license: public domain (USGS)
license: CC-BY-4.0
updated: '2026-11-01'
review:
  status: draft
  method: assistant
  checked_values: 20
  unreachable: 0
  caveats: 2
  note: Written by an AI assistant on 2026-11-01 from pages and PDFs fetched in that run. Values are as printed. The BS 1407 hardening and tempering rows come from a PDF without a text layer, and the 1.2210 rows describe the European equivalent.
story:
  recipe:
    line: Silver steel to BS 1407 is an iron-based, high-carbon tool steel with chromium, manganese, and small silicon, phosphorus and sulphur contents. It is supplied spheroidised and annealed, and the bar is ground and polished to close tolerances. Wikipedia notes that the name comes from the polished look of the bar, not from any silver in the alloy.
    parts:
      - name: Iron
        symbol: Fe
        share: balance
        role: The matrix. The certificate analysis is the balance to iron.
      - name: Carbon
        symbol: C
        share: 0.95 to 1.25 %
        role: Sets the hardness reached on quenching. The supplier says the high carbon content lets the steel be hardened for considerable wear resistance.
      - name: Chromium
        symbol: Cr
        share: 0.35 to 0.45 %
        role: Adds strength and hardenability, as the supplier states.
      - name: Manganese
        symbol: Mn
        share: 0.25 to 0.45 %
        role: Listed in the analysis. The sources give no separate role for it.
      - name: Silicon
        symbol: Si
        share: 0.4 % maximum
        role: Listed in the analysis. The sources give no separate role for it.
      - name: Phosphorus
        symbol: P
        share: 0.045 % maximum
        role: Impurity limit set by the analysis.
      - name: Sulphur
        symbol: S
        share: 0.045 % maximum
        role: Impurity limit set by the analysis.
  risk_groups:
    - title: For people
      level: 0
      verdict: 'Solid steel: no hazard; dust and fume are the concern'
      lead: Solid steel presents no inhalation, ingestion or contact hazard according to the grouped safety data sheet for carbon, alloy and tool steels. Dust and fume from machining, grinding and welding are the concern.
      points:
        - label: The solid bar
          line: The grouped safety data sheet says that carbon, alloy and tool steels in their solid state present no inhalation, ingestion or contact health hazard. It does not name silver steel.
        - label: Dust and fume
          line: Dusts and fumes from burning, melting, welding, sawing, brazing, grinding and machining may be hazardous. Excessive exposure can irritate the eyes, nose and throat.
        - label: Protection
          line: Use local exhaust ventilation and a NIOSH approved dust, mist or fume respirator when welding or burning this metal.
    - title: If the steel is overheated or over-tempered
      lead: These are workshop heat-treatment limits, not hazards.
      points:
        - label: Stress relief
          line: Stress relieving at about 650 °C is carried out to reduce distortion during heat treatment, according to the 1.2210 datasheet.
        - label: Over-tempering
          line: Tempering at 400 °C leaves the 1.2210 grade at 51 HRC, against 62 HRC after tempering at 200 °C.
    - title: Rust in storage
      lead: The sources say the steel rusts, so keep it protected in storage and in handling.
      points:
        - label: Protection
          line: The 1.2210 datasheet says the steel is not corrosion resistant and will rust unless protected.
  why: 'Silver steel is a precision-ground, high-carbon tool steel. Its supplier sells it as bright ground bar for shafts, pins, punches and tooling, and says the high carbon content lets it be hardened for wear resistance. The bar is supplied in the annealed condition, which makes it easy to machine before hardening. It is not stainless: the 1.2210 datasheet says it rusts unless protected.'
  uses:
    - where: Precision tooling and small parts
      line: The supplier lists punches, dowels, mandrels, spindles, drill bushes, shafts, engraving tools, knurls, collets and lathe centres as customer applications for its BS 1407 silver steel.
    - where: Hand tools and punches
      line: Wikipedia says silver steel has been widely used to make punches, engravers and screwdrivers.
    - where: Drills, broaching and cutting tools (1.2210 equivalent)
      line: The 1.2210 datasheet lists spiral and tap drills, broaching tools, engraving tools, ejectors and metal saws as applications for the grade.
  can_do:
    - label: Hardness
      line: Hardens to 64 to 66 HRC after quenching, according to the 1.2210 datasheet.
    - label: Tempering
      line: Keeps 62 HRC after tempering at 200 °C, according to the 1.2210 tempering table.
    - label: Machining
      line: Is supplied annealed at no more than 285 HB, so it can be machined before it is hardened.
    - label: Finish
      line: Is ground and polished to close tolerances with a bright surface, as the supplier describes.
  compare: Silver steel is a plain high-carbon, chromium steel. Its certificate analysis range has no vanadium line, while the 1.2210 datasheet lists vanadium and higher chromium, so the 1.2210 values describe a close relative rather than the BS 1407 bar. The 1.2210 tempering table shows hardness falling steadily as the tempering temperature rises, from 62 HRC at 200 °C to 51 HRC at 400 °C.
  compare_rows:
    - label: Hardness as delivered
      benchmark: hardness_brinell
    - label: Hardness after quenching (1.2210)
      benchmark: hardness_rockwell_c
    - label: Density (1.2210)
      benchmark: density
  handling:
    - Stress relieve after heavy machining at about 650 °C for one to two hours, then air cool (1.2210 datasheet).
    - Temper after hardening. The 1.2210 tempering table gives 62 HRC at 200 °C and 51 HRC at 400 °C.
    - Keep bare bar dry and protected, because it rusts.
    - Wear dust and fume protection when grinding, welding or burning.
  good_for:
    - Precision shafts, pins and punches that need bright ground bar. The supplier says it is ground and polished to close tolerances.
    - Hardened wear parts such as punches and ejectors. The 1.2210 datasheet gives 64 to 66 HRC after quenching.
  watch_out:
    - Rusts unless protected. The 1.2210 datasheet says the steel is not corrosion resistant.
    - 'Hardness falls as tempering temperature rises: 62 HRC at 200 °C and 51 HRC at 400 °C (1.2210).'
    - Distortion in hardening. Stress relief at about 650 °C reduces it, according to the 1.2210 datasheet.
  verdict: Silver steel is a precision tool steel for small hardened parts. It is machined soft, hardened by quenching, tempered, and must be protected from rust.