Custom 465 stainless steel Custom 465 (UNS S46500, AMS 5936)

spore: profile
id: custom-465
spore_version: 0.2
family: stainless-precipitation-hardening
name: Custom 465 stainless steel
abbreviation: Custom 465 (UNS S46500, AMS 5936)
role: precipitation-hardening structural alloy
category: metals
type: steels-and-stainless
summary: |
  Custom 465 stainless steel (UNS S46500, AMS 5936) is a martensitic, age-hardenable stainless steel. Service Steel Aerospace lists its typical strength as high as 1758 MPa (255 ksi), with fracture toughness of 88-99 MPa-square-root-meter. Its aged H950 and H1000 conditions have yield strengths of 220 ksi and 200 ksi in the datasheet, and the vendor says its corrosion resistance approaches that of Type 304 stainless. Public test data for the alloy are thin, and no flight or space result was found.
best_for: Shafts, fasteners, actuators and landing-gear class parts that need about 200 to 220 ksi yield strength in aged conditions with stainless corrosion resistance (vendor claims)
weakest_at: 'Public test data: no melting point, hardness, salt-spray or space test values were found in the sources read'
identity:
  formula: Fe balance with 11.00 to 12.50 Cr, 10.75 to 11.25 Ni, 0.75 to 1.25 Mo, 1.50 to 1.80 Ti, 0.90 to 1.35 Al, max 0.02 C, max 0.25 Mn, max 0.25 Si, max 0.01 S, max 0.015 P, max 0.01 N (wt%, UNS S46500 composition limits)
  source: ssa-product
  where: Chemical Composition table in the Service Steel Aerospace datasheet (ssa-ds) and the composition table on the product page (ssa-product)
  designations:
    - system: UNS
      code: S46500
      source: ssa-product
      where: 'Product heading: Custom 465 Stainless Steel - AMS 5936 - UNS S46500'
    - system: AMS
      code: '5936'
      source: ssa-product
      where: 'Product heading: Custom 465 Stainless Steel - AMS 5936 - UNS S46500'
    - system: ASTM
      code: A564
      source: ti-industries
      where: 'Specifications list: ASTM A564'
    - system: ASTM
      code: F899
      note: sizes 3 in diameter and below
      source: ssa-ds
      where: 'Common Specifications list: ASTM F899 for sizes 3 in diameter and below'
    - system: Trade name
      code: Custom 465
      source: ssa-product
      where: 'Product heading and text: Custom 465 is a registered trademark of Carpenter Technology Corporation'
    - system: Trade name
      code: Alloy 465
      source: ssa-ds
      where: Common Trade Names list
    - system: Trade name
      code: C465
      source: ssa-ds
      where: Common Trade Names list
    - system: Trade name
      code: 465 Stainless
      source: ssa-ds
      where: Common Trade Names list
tags:
  applications:
    - structures
    - mechanisms
    - propulsion-and-tanks
properties:
  - benchmark: density
    label: Density, Cond H1000
    value: 7.84
    unit: g/cm3
    scope: material
    conditions:
      condition: H1000 (age condition as printed in the table)
    method: Value printed in the physical properties table of a stainless steel supplier product page
    status: ground
    source: ssa-product
    where: Physical Properties table, row Cond H1000, column g/cm3
  - benchmark: density
    label: Density, annealed
    value: 7.81
    unit: g/cm3
    scope: material
    conditions:
      condition: Annealed (solution annealed, the condition in which the alloy is normally supplied)
    method: Value printed in the physical properties table of a stainless steel supplier product page
    status: ground
    source: ssa-product
    where: Physical Properties table, row Annealed, column g/cm3
  - benchmark: density
    label: Density, Cond H1000 (imperial)
    value: 0.2822
    unit: lbs/in3
    scope: material
    conditions:
      condition: H1000 (age condition as printed in the table)
    method: Value printed in the physical properties table of a stainless steel supplier product page
    status: ground
    source: ssa-product
    where: Physical Properties table, row Cond H1000, column lbs/in3
  - benchmark: yield_strength
    label: Yield strength 0.2% offset, H950 longitudinal
    value: 220
    unit: ksi
    scope: material
    conditions:
      temper: H950 (aged)
      orientation: longitudinal
      measure: 0.2% offset
      product_form: not stated in the datasheet
    method: Value printed in the mechanical properties table of the supplier datasheet
    status: ground
    source: ssa-ds
    where: Mechanical Properties table, row H950 Longitudinal, column Yield 0.2% offset
  - benchmark: yield_strength
    label: Yield strength 0.2% offset, H950 transverse
    value: 220
    unit: ksi
    scope: material
    conditions:
      temper: H950 (aged)
      orientation: transverse
      measure: 0.2% offset
      product_form: not stated in the datasheet
    method: Value printed in the mechanical properties table of the supplier datasheet
    status: ground
    source: ssa-ds
    where: Mechanical Properties table, row H950 Transverse, column Yield 0.2% offset
  - benchmark: yield_strength
    label: Yield strength 0.2% offset, H1000 longitudinal
    value: 200
    unit: ksi
    scope: material
    conditions:
      temper: H1000 (aged)
      orientation: longitudinal
      measure: 0.2% offset
      product_form: not stated in the datasheet
    method: Value printed in the mechanical properties table of the supplier datasheet
    status: ground
    source: ssa-ds
    where: Mechanical Properties table, row H1000 Longitudinal, column Yield 0.2% offset
  - benchmark: yield_strength
    label: Yield strength 0.2% offset, H1000 transverse
    value: 200
    unit: ksi
    scope: material
    conditions:
      temper: H1000 (aged)
      orientation: transverse
      measure: 0.2% offset
      product_form: not stated in the datasheet
    method: Value printed in the mechanical properties table of the supplier datasheet
    status: ground
    source: ssa-ds
    where: Mechanical Properties table, row H1000 Transverse, column Yield 0.2% offset
  - benchmark: yield_strength
    label: Yield strength range, Rp 0.2 offset (min to max)
    value: 170
    value_high: 270
    bound: range
    unit: ksi
    scope: material
    conditions:
      basis: minimum and maximum of the yield strength range printed in Table 3; the condition and orientation are not printed
    method: Range printed in a supplier product page table of mechanical properties
    status: ground
    source: ti-industries
    where: Table 3 (mechanical properties), row Yield Strength Range (Rp 0.2 Offset) (ksi)
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, H950 longitudinal
    value: 240
    unit: ksi
    scope: material
    conditions:
      temper: H950 (aged)
      orientation: longitudinal
      product_form: not stated in the datasheet
    method: Value printed in the mechanical properties table of the supplier datasheet
    status: ground
    source: ssa-ds
    where: Mechanical Properties table, row H950 Longitudinal, column Tensile
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, H1000 longitudinal
    value: 220
    unit: ksi
    scope: material
    conditions:
      temper: H1000 (aged)
      orientation: longitudinal
      product_form: not stated in the datasheet
    method: Value printed in the mechanical properties table of the supplier datasheet
    status: ground
    source: ssa-ds
    where: Mechanical Properties table, row H1000 Longitudinal, column Tensile
  - benchmark: ultimate_tensile_strength
    label: Tensile strength range (min to max)
    value: 190
    value_high: 280
    bound: range
    unit: ksi
    scope: material
    conditions:
      basis: minimum and maximum of the tensile strength range printed in Table 3; the condition and orientation are not printed
    method: Range printed in a supplier product page table of mechanical properties
    status: ground
    source: ti-industries
    where: Table 3 (mechanical properties), row Tensile Strength Range (R m ) (ksi)
  - benchmark: ultimate_tensile_strength
    label: Typical strength, upper figure
    value: 1758
    unit: MPa
    scope: material
    conditions:
      basis: statement that the typical strength can be as high as 1758 MPa (255 ksi); the condition is not stated
    method: Typical upper figure printed in the opening text of a supplier product page
    status: ground
    source: ssa-product
    where: Opening paragraph, sentence beginning The typical strength of this alloy
  - benchmark: elongation
    label: Elongation, H950 longitudinal
    value: 10
    unit: '%'
    scope: material
    conditions:
      temper: H950 (aged)
      orientation: longitudinal
      gauge: 2 in or 4D (as printed)
    method: Value printed in the mechanical properties table of the supplier datasheet
    status: ground
    source: ssa-ds
    where: Mechanical Properties table, row H950 Longitudinal, column Elongation 2 in or 4D
  - benchmark: elongation
    label: Elongation, H950 transverse
    value: 8
    unit: '%'
    scope: material
    conditions:
      temper: H950 (aged)
      orientation: transverse
      gauge: 2 in or 4D (as printed)
    method: Value printed in the mechanical properties table of the supplier datasheet
    status: ground
    source: ssa-ds
    where: Mechanical Properties table, row H950 Transverse, column Elongation 2 in or 4D
  - benchmark: elongation
    label: Elongation range (min to max)
    value: 2.3
    value_high: 14
    bound: range
    unit: '%'
    scope: material
    conditions:
      basis: minimum and maximum printed in Table 3; gauge is AL = 5 x diameter as printed; the condition is not printed
    method: Range printed in a supplier product page table of mechanical properties
    status: ground
    source: ti-industries
    where: Table 3 (mechanical properties), row Elongation (AL=5 x Ø)
  - benchmark: reduction_of_area
    label: Reduction of area, H950 longitudinal
    value: 45
    unit: '%'
    scope: material
    conditions:
      temper: H950 (aged)
      orientation: longitudinal
    method: Value printed in the mechanical properties table of the supplier datasheet
    status: ground
    source: ssa-ds
    where: Mechanical Properties table, row H950 Longitudinal, column Reduction of Area
  - benchmark: reduction_of_area
    label: Reduction of area, H1000 longitudinal
    value: 50
    unit: '%'
    scope: material
    conditions:
      temper: H1000 (aged)
      orientation: longitudinal
    method: Value printed in the mechanical properties table of the supplier datasheet
    status: ground
    source: ssa-ds
    where: Mechanical Properties table, row H1000 Longitudinal, column Reduction of Area
  - benchmark: fracture_toughness
    label: Fracture toughness, typical
    value: 88
    value_high: 99
    bound: range
    unit: MPa-square-root-meter
    scope: material
    conditions:
      basis: statement of about 88-99 MPa-square-root-meter (80-90 ksi-square-root inch); the condition is not stated
    method: Range printed in the opening text of a supplier product page
    status: ground
    source: ssa-product
    where: Opening paragraph, sentence beginning The typical strength of this alloy
  - benchmark: elastic_modulus
    label: Modulus of elasticity
    value: 32000
    unit: ksi
    scope: material
    conditions:
      temperature: not stated
      condition: not stated
    method: Value printed in the mechanical properties table of a stainless steel supplier product page
    status: ground
    source: ti-industries
    where: Table 3 (mechanical properties), row Modulus of Elasticity (ksi) (E)
  - benchmark: electrical_conductivity
    label: Electrical conductivity
    value: 2.05
    unit: '% IACS'
    scope: material
    conditions:
      temperature: not stated
      condition: not stated
    method: Value printed in the physical properties table of a stainless steel supplier product page
    status: ground
    source: ti-industries
    where: Table 2 (physical properties), column Electrical conductivity (% IACS)
  - benchmark: thermal_conductivity
    label: Thermal conductivity
    value: 97
    unit: BTU-in/hr-ft²-°F
    scope: material
    conditions:
      temperature: not stated
      condition: not stated
    method: Value printed in the physical properties table of a stainless steel supplier product page
    status: ground
    source: ti-industries
    where: Table 2 (physical properties), column Thermal conductivity (BTU-in/hr-ft²-°F)
corrosion:
  - environment: General service, no test condition given
    headline: The vendors say general corrosion resistance is close to Type 304 stainless.
    effect: Titanium Industries says general corrosion resistance is similar to type 304, and Service Steel Aerospace says it approaches that of Type 304. Neither source gives a salt-spray, humidity or immersion test result.
    rating: low
    conditions:
      basis: vendor statements only; no test environment or duration given
    source: ti-industries
    where: Product description, first paragraph
  - environment: Stressed parts in corrosive media
    headline: The alloy is described as having excellent resistance to stress corrosion cracking.
    effect: Service Steel Aerospace describes excellent resistance to stress corrosion cracking. No threshold stress, test duration or failure time is given in the sources read.
    rating: unknown
    conditions:
      basis: vendor description; no stress corrosion test data read
    source: ssa-product
    where: Grade features paragraph, sentence beginning This grade features
risks:
  hazards:
    - text: 'PubChem''s GHS summary for nickel metal, not this alloy, lists H317, H351 and H372 in its first notification block, with signal word Danger. The ECHA C&L summary for nickel gives H317 (99.9%): May cause an allergic skin reaction.'
      ghs:
        - H317
        - H351
        - H372
      source: pubchem-nickel
      where: GHS Classification section, first notification block and ECHA C&L Notifications Summary (CID 935)
    - text: PubChem's GHS summary for chromium, not this alloy, gives H317 (20.7%) in its ECHA C&L summary, and states that the chemical does not meet GHS hazard criteria for 50% (1202 of 2404) of reports.
      ghs:
        - H317
      source: pubchem-chromium
      where: GHS Classification section, ECHA C&L Notifications Summary (CID 23976)
  failure_risks:
    - mode: Low strength when the aging step is skipped
      trigger: Part supplied in the solution-annealed condition (Condition A) and not age-hardened
      consequence: The vendor states that high strength needs an additional age-hardening step; the strengths in this profile apply to aged conditions only.
      severity: moderate
      source: ssa-product
      where: Heat Treatment section, sentence beginning Achieving high strength levels
    - mode: Delayed refrigeration step
      trigger: More than 24 hours between solution annealing and the refrigeration step
      consequence: The datasheet says the refrigeration step should follow within a 24-hour period; it does not state what happens after a longer delay.
      severity: low
      source: ssa-ds
      where: Heat Treatment section, final bullets
  side_effects: []
  handling:
    - text: 'Heat treatment as printed: the alloy is normally supplied in Condition A (solution annealed). Heat to 1800° F ± 15° F (982° C ± 8° C) and hold for 1 hour, then quench parts under 12 in or air cool parts over 12 in.'
      source: ssa-ds
      where: Heat Treatment section, first bullet
    - text: Refrigerate to -100° F (-73° C) and hold for eight hours, then warm to room temperature. The datasheet asks that this step follow solution annealing within a 24-hour period.
      source: ssa-ds
      where: Heat Treatment section, second and third bullets
    - text: 'Age hardening for high strength: heat to 900 to 1150° and hold 4 to 8 hours, air cool sizes under 3 in and quench sizes over 3 in. The datasheet prints the age temperature without a unit after 1150°.'
      source: ssa-product
      where: Heat Treatment section, paragraph on the age hardening step
    - text: 'Hot working: solution anneal before hardening, then heat to 1850-2000° F (1010-1093° C) and air cool. Cold forming by drawing or rolling is readily done.'
      source: ssa-ds
      where: Hot and cold working section
    - text: Machinability is best in the overaged H1150M condition, and can also be done in the solution annealed condition.
      source: ssa-ds
      where: Machinability section
  mitigations: []
uses:
  - application: structures
    device: Landing gear, flap tracks, engine mounts and slat tracks
    example: Service Steel Aerospace lists landing gear, flap tracks, engine mounts, slat tracks and actuators as aerospace uses of Custom 465, and says it can replace 300M and AISI 4340 steels that must otherwise be plated for corrosion protection.
    source: ssa-product
    where: Opening text and Applications list, Aerospace
  - application: mechanisms
    device: Actuators and small shafts
    example: Titanium Industries lists typical uses as small turbine engine shafts, firearms, medical instruments, fasteners and actuators.
    source: ti-industries
    where: Description, Typical uses paragraph
  - application: propulsion-and-tanks
    device: Small turbine engine shafts
    example: Titanium Industries lists small turbine engine shafts as the first typical use of Stainless Steel Grade 465.
    source: ti-industries
    where: Description, Typical uses paragraph
supply:
  - subject: Nickel
    producers:
      - country: Indonesia
        share_percent: 66.7
        year: 2025
      - country: Philippines
        share_percent: 6.9
        year: 2025
      - country: Russia
        share_percent: 5.1
        year: 2025
      - country: Canada
        share_percent: 3.6
        year: 2025
      - country: New Caledonia (France)
        share_percent: 3.6
        year: 2025
      - country: China
        share_percent: 3.1
        year: 2025
    critical_lists: []
    recycling: 'USGS: nickel recovered from scrap accounted for approximately 60% of apparent consumption in 2025, and most secondary nickel is the nickel content of stainless-steel scrap.'
    substitutes:
      - 'USGS: low-nickel, duplex, or ultrahigh-chromium stainless steels have been substituted for austenitic grades in construction; titanium alloys can substitute for nickel or nickel-base alloys in corrosive environments.'
    source: usgs-nickel
    where: World Mine Production and Reserves table, mine production 2025e (world total 3,900,000 in metric tons, nickel content; shares calculated by Space Mushroom); Recycling; Substitutes; Domestic Production and Use (stainless and alloy steel more than 85% of domestic consumption)
  - 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
      - country: Zimbabwe
        share_percent: 3.9
        year: 2025
    critical_lists: []
    recycling: 'USGS: recycled chromium contained in reported stainless-steel scrap receipts accounted for 21% of apparent consumption in 2025.'
    substitutes:
      - 'USGS: chromium has no substitute in stainless steel, the leading end use, or in superalloys.'
    source: usgs-chromium
    where: World Mine Production and Reserves table, mine production 2025e (world total 51,000 thousand t; chromite ore reported in gross weight; shares calculated by Space Mushroom); Recycling; Substitutes
  - subject: Molybdenum
    producers:
      - country: China
        share_percent: 37.3
        year: 2025
      - country: Chile
        share_percent: 16.2
        year: 2025
      - country: United States
        share_percent: 15.4
        year: 2025
      - country: Peru
        share_percent: 15
        year: 2025
      - country: Mexico
        share_percent: 6.5
        year: 2025
    critical_lists: []
    recycling: 'USGS: molybdenum recycled as part of new and old steel and other scrap may be as much as 30% of the apparent supply of molybdenum.'
    substitutes:
      - 'USGS: there is little substitution for molybdenum in steels and cast irons; potential substitutes in alloy steels include boron, chromium, niobium and vanadium.'
    source: usgs-molybdenum
    where: World Mine Production and Reserves table, mine production 2025e (world total 260,000 thousand t; shares calculated by Space Mushroom); Recycling; Substitutes; Events, Trends, and Issues (China, Chile, the United States, Peru and Mexico account for 90% of production)
media: []
documents:
  - title: Custom 465 stainless steel product page, Titanium Industries (UNS S46500)
    type: datasheet
    url: https://titanium.com/alloys/stainless-steel/stainless-steel-custom-465/
    year: 2026
  - title: Custom 465 stainless steel product page, Service Steel Aerospace (AMS 5936, UNS S46500)
    type: datasheet
    url: https://ssa-corp.com/es/Custom-465-stainless-AMS-5936-UNS-S46500.php
    year: 2026
  - title: Custom 465 stainless steel data sheet, Service Steel Aerospace (PDF)
    type: datasheet
    url: https://ssa-corp.com/documents/Data%20Sheet%20Custom-465-AMS-5936-UNS-S46500.pdf
    year: 2026
  - title: 'USGS Mineral Commodity Summaries 2026: Nickel'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf
    year: 2026
  - 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: Molybdenum'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-molybdenum.pdf
    year: 2026
  - title: 'PubChem compound record: Nickel (CID 935), GHS classification'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/Nickel
    year: 2026
  - title: 'PubChem compound record: Chromium (CID 23976), GHS classification'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/Chromium
    year: 2026
gaps:
  - 'No melting point value: the Titanium Industries physical properties table prints a dash for melting point.'
  - 'Hardness not recorded: Titanium Industries prints a Brinell range (271 to 560) with no unit.'
  - 'Specific heat not recorded: printed as 0.107 with no unit.'
  - 'Thermal expansion not recorded: printed only as a decimal in 1/°F, and this profile does not convert units.'
  - Fracture toughness and reduction of area are not in the canonical property list; recorded under the snake_case names fracture_toughness and reduction_of_area.
  - The 1758 MPa (255 ksi) figure is a vendor typical upper value with no temper, orientation or test method printed.
  - Mechanical values come from a distributor and a service center copy of one datasheet; they are nominal and cover only the H950 and H1000 aged conditions, so H900, H1050 and H1100 strengths are not recorded.
  - Titanium Industries states that its alloy data are for reference only and not for design.
  - Critical-mineral list status for nickel, chromium and molybdenum was not verified in this run; critical_lists is left empty.
  - 'Iron and titanium supply not recorded: no cited supply page for either was read.'
  - No flight, vacuum, outgassing, atomic-oxygen or radiation data for Custom 465 was found; no space source was located.
  - No salt-spray, humidity or immersion corrosion test results were found in the sources read.
  - Hazard data are for the component metals (nickel and chromium, via PubChem), not for the alloy; no SDS for Custom 465 itself was found.
  - Carpenter Technology's own datasheet was not read; the datasheets used are copies published by Service Steel Aerospace and Titanium Industries.
sources:
  ti-industries:
    title: Stainless Steel Grade 465 (UNS S46500) product page, Titanium Industries
    id: UNS S46500; ASTM A564; ASTM F899; AMS 5936
    url: https://titanium.com/alloys/stainless-steel/stainless-steel-custom-465/
    year: 2026
    kind: web
    license: Supplier web page (cited, not reproduced)
  ssa-product:
    title: Custom 465 Stainless Steel - AMS 5936 - UNS S46500, Service Steel Aerospace product page
    id: AMS 5936; UNS S46500
    url: https://ssa-corp.com/es/Custom-465-stainless-AMS-5936-UNS-S46500.php
    year: 2026
    kind: web
    license: Supplier web page (cited, not reproduced)
  ssa-ds:
    title: Custom 465 Stainless Steel - AMS 5936 - UNS S46500, Service Steel Aerospace data sheet (PDF)
    id: AMS 5936; UNS S46500; common trade names Custom 465, Alloy 465, C465, 465 Stainless
    url: https://ssa-corp.com/documents/Data%20Sheet%20Custom-465-AMS-5936-UNS-S46500.pdf
    year: 2026
    kind: datasheet
    license: Supplier data sheet (cited, not reproduced)
  usgs-nickel:
    title: 'Mineral Commodity Summaries 2026: Nickel'
    id: USGS MCS 2026, February 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  usgs-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-molybdenum:
    title: 'Mineral Commodity Summaries 2026: Molybdenum'
    id: USGS MCS 2026, February 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-molybdenum.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  pubchem-nickel:
    title: 'PubChem compound record: Nickel (CID 935), GHS classification and ECHA C&L summary'
    id: CID 935
    url: https://pubchem.ncbi.nlm.nih.gov/compound/Nickel
    year: 2026
    kind: database
    license: public domain (NCBI)
  pubchem-chromium:
    title: 'PubChem compound record: Chromium (CID 23976), GHS classification and ECHA C&L summary'
    id: CID 23976
    url: https://pubchem.ncbi.nlm.nih.gov/compound/Chromium
    year: 2026
    kind: database
    license: public domain (NCBI)
license: CC-BY-4.0
updated: '2026-11-01'
review:
  status: draft
  method: assistant
  checked_values: 21
  unreachable: 0
  caveats: 4
  note: 'Values read by an AI assistant on 2026-11-01 from the two product pages and the Service Steel Aerospace data sheet PDF; USGS and PubChem figures read from the PDFs and PubChem JSON. Caveats: strengths are nominal values for aged H950 and H1000 only; the vendor 1758 MPa figure has no condition; supply shares are calculated; hazard data are for component metals.'
story:
  recipe:
    line: Custom 465 is an iron-based martensitic stainless steel with 11 to 12.5 percent chromium, about 11 percent nickel and about 1 percent molybdenum, plus titanium and aluminium that form the age-hardening precipitates. Service Steel Aerospace says it is double vacuum melted and normally supplied in the solution-annealed condition, then hardened by a heat treatment.
    parts:
      - name: Iron
        symbol: Fe
        share: balance (wt%)
        role: The matrix. The alloy is martensitic after hardening, and iron makes up the rest of the composition.
      - name: Chromium
        symbol: Cr
        share: 11.00 to 12.50 wt%
        role: Gives stainless corrosion resistance; the vendor says resistance is close to Type 304.
      - name: Nickel
        symbol: Ni
        share: 10.75 to 11.25 wt%
        role: Helps keep the alloy tough and supports the martensitic structure.
      - name: Molybdenum
        symbol: Mo
        share: 0.75 to 1.25 wt%
        role: Adds strength and resistance to pitting.
      - name: Titanium
        symbol: Ti
        share: 1.50 to 1.80 wt%
        role: Forms the precipitates that harden the alloy during the age treatment.
      - name: Aluminium
        symbol: Al
        share: 0.90 to 1.35 wt%
        role: Also takes part in the age-hardening precipitates.
  risk_groups:
    - title: For people
      verdict: Mixed; hazards come from its nickel and chromium
      lead: Hazard data are for the component metals, not for the finished alloy, and no safety data sheet for Custom 465 itself was read.
      points:
        - label: Nickel and chromium
          line: PubChem's summary for nickel metal lists H317 (99.9%) as an allergic skin hazard, with H351 and H372 in one notification block. Its chromium summary lists H317 (20.7%).
        - label: Dust and fume
          line: No source read gives a dust or welding fume limit for this alloy, so treat grinding and welding dust as a hazard until a data sheet says otherwise.
    - title: If it fails
      lead: The failure routes below come from the vendor and datasheet. No field or flight failure record was found.
      points:
        - label: Skipped aging
          line: The vendor says the high strength needs an extra age-hardening step, so parts left in the annealed condition are much weaker.
        - label: Late refrigeration
          line: The datasheet asks for refrigeration within a 24-hour period after solution annealing and does not state what a longer delay does.
    - title: Handling and storage
      points:
        - label: Heat treatment
          line: 'Follow the cycle in the datasheet: solution anneal, refrigerate within 24 hours, then age harden.'
        - label: Machining
          line: The datasheet says machining is best in the overaged H1150M condition.
  why: 'Custom 465 is a martensitic stainless steel that gets its strength from an age-hardening treatment. Service Steel Aerospace says it combines high strength, toughness and corrosion resistance, and that it can replace 300M and AISI 4340 steels that otherwise need a coating for corrosion protection. The aged H950 and H1000 conditions are listed at 220 ksi and 200 ksi yield strength. That combination explains where it is chosen: small shafts, actuators, fasteners and landing-gear class parts.'
  uses:
    - where: Aerospace structures
      line: Service Steel Aerospace lists landing gear, flap tracks, engine mounts, slat tracks and actuators as aerospace uses of Custom 465.
    - where: Shafts, actuators and fasteners
      line: Titanium Industries lists small turbine engine shafts, firearms, medical instruments, fasteners and actuators as typical uses.
  can_do:
    - label: Carry load
      benchmark: yield_strength
      value: 220 ksi
      line: Yield strength of 220 ksi in the H950 condition, longitudinal, per the Service Steel Aerospace data sheet.
    - label: Keep toughness
      benchmark: fracture_toughness
      line: Fracture toughness of 88 to 99 MPa-square-root-meter, per the Service Steel Aerospace product page (vendor statement).
    - label: Stay stiff
      benchmark: elastic_modulus
      value: 32000 ksi
      line: Modulus of elasticity of 32000 ksi, per Titanium Industries.
    - label: Resist corrosion
      line: Corrosion resistance close to Type 304 in general, according to the vendor; no test data were found.
  compare: Service Steel Aerospace positions Custom 465 as a corrosion resistant replacement for 300M and AISI 4340 steels, which must be plated or coated for corrosion protection, and says its corrosion resistance approaches that of Type 304 stainless. Titanium Industries states that its general corrosion resistance is similar to type 304. These are vendor statements; the rows below compare this grade's own aged-condition values, because no like-for-like test of Custom 465 against other grades was read in this run.
  compare_rows:
    - label: Density
      benchmark: density
    - label: Yield strength
      benchmark: yield_strength
    - label: Modulus of elasticity
      benchmark: elastic_modulus
  handling:
    - Specify the aged condition (H950, H1000 or another), because the strength values depend on it.
    - Keep the solution anneal, refrigeration and aging steps within the times the datasheet gives.
    - Use a dust mask or extraction for grinding dust, pending a safety data sheet for the alloy itself.
  good_for:
    - 'High strength in aged conditions: 220 ksi yield in H950 longitudinal, per the datasheet.'
    - Corrosion resistance close to Type 304 (vendor statement).
  watch_out:
    - Strength depends on the aged condition and the orientation; the aged values here are nominal.
    - Stress corrosion resistance is described as excellent, but no stress corrosion test data were found.
    - Nickel and chromium supply is concentrated (Indonesia for nickel; South Africa for chromite ore).
    - No space, vacuum, outgassing or radiation data were found for this alloy.
  verdict: Custom 465 is a high-strength, age-hardened stainless steel with vendor claims of Type 304 corrosion resistance and excellent stress corrosion cracking resistance. Its aged yield strengths (220 ksi and 200 ksi in the datasheet) are well documented from two copies of one datasheet, but its corrosion and space performance are not backed by test data in the sources read.