Super duplex stainless steel 2507 2507 (UNS S32750)

spore: profile
id: stainless-2507
spore_version: 0.2
family: stainless-duplex
name: Super duplex stainless steel 2507
abbreviation: 2507 (UNS S32750)
role: corrosion-resistant structural alloy
category: metals
type: steels-and-stainless
summary: |
  SAF 2507 (UNS S32750, EN 1.4410) is a super duplex stainless steel with a nominal 25 percent chromium, 7 percent nickel, 4 percent molybdenum and 0.3 percent nitrogen. Its structure is a mix of ferrite and austenite, with 35 to 55 percent ferrite in solution-annealed bar. Alleima gives a minimum pitting resistance equivalent (PRE) of 41 for bar and 42.5 for seamless tube, and a minimum proof strength of 550 MPa in its tube and bar datasheets. Its listed uses are seawater, offshore and subsea, oil and gas, and desalination equipment.
best_for: Chloride-bearing seawater, subsea and sour oil and gas service that needs high strength and pitting resistance, in solution-annealed tube, bar and forgings
weakest_at: Prolonged exposure above 250 °C, which lowers impact strength, and hydrogen-induced cracking in cathodically protected subsea steel
identity:
  formula: Fe balance; nominal 25 Cr, 7 Ni, 4 Mo, 0.3 N (wt%); maximum 0.03 C, 1.2 Mn, 0.8 Si, 0.035 P, 0.015 S, 0.5 Cu (wt%)
  source: alleima-bar
  where: Chemical composition (nominal) table, bar datasheet. The UNS and EN numbers also appear in the Wikipedia SAF 2507 article.
  designations:
    - system: UNS
      code: S32750
    - system: EN
      code: '1.4410'
    - system: EN name
      code: X2CrNiMoN25-7-4
    - system: Name
      code: SAF 2507
    - system: ASTM
      code: A182 Grade F53
      note: forgings from billets
tags:
  environments: []
  stresses: []
  applications:
    - structures
    - mechanisms
properties:
  - benchmark: yield_strength
    value: 550
    bound: lower
    unit: MPa
    scope: material
    conditions:
      form: seamless tube and pipe, wall up to 20 mm
      temper: solution annealed and quenched
      temperature: 20 °C
      basis: minimum 0.2 percent offset (Rp0.2)
    method: Mechanical properties table at 20 °C, minimum as printed (≥550 MPa)
    status: ground
    source: alleima-tube
    where: Mechanical properties, At 20 °C table, Rp0.2 column
  - benchmark: yield_strength
    value: 480
    bound: lower
    unit: MPa
    scope: material
    conditions:
      form: seamless tube and pipe, wall up to 20 mm
      temper: solution annealed and quenched
      temperature: 100 °C
      basis: minimum 0.2 percent offset (Rp0.2)
    method: High-temperature proof strength table, minimum as printed (100 °C row)
    status: ground
    source: alleima-tube
    where: At high temperatures, proof strength Rp0.2 minimum table, 100 °C row
  - benchmark: yield_strength
    value: 395
    bound: lower
    unit: MPa
    scope: material
    conditions:
      form: seamless tube and pipe, wall up to 20 mm
      temper: solution annealed and quenched
      temperature: 300 °C
      basis: minimum 0.2 percent offset (Rp0.2)
    method: High-temperature proof strength table, minimum as printed (300 °C row)
    status: ground
    source: alleima-tube
    where: At high temperatures, proof strength Rp0.2 minimum table, 300 °C row
  - benchmark: yield_strength
    value: 530
    bound: lower
    unit: MPa
    scope: material
    conditions:
      form: forgings produced from billets (ASTM A182 values valid, as footnoted)
      temper: solution annealed and quenched
      temperature: 20 °C
      basis: minimum 0.2 percent offset (Rp0.2)
    method: Mechanical properties table at 20 °C, minimum as printed (≥530, footnote c)
    status: ground
    source: alleima-billet
    where: Mechanical properties, At 20 °C table, Rp0.2 column
  - benchmark: ultimate_tensile_strength
    value: 800
    value_high: 1000
    bound: range
    unit: MPa
    scope: material
    conditions:
      form: seamless tube and pipe, wall up to 20 mm
      temper: solution annealed and quenched
      temperature: 20 °C
    method: Mechanical properties table at 20 °C, range as printed (800-1000 MPa)
    status: ground
    source: alleima-tube
    where: Mechanical properties, At 20 °C table, Rm column
  - benchmark: ultimate_tensile_strength
    value: 760
    value_high: 930
    bound: range
    unit: MPa
    scope: material
    conditions:
      form: bar, solution annealed, quenched and peel-turned
      temper: solution annealed and quenched
      temperature: 20 °C
    method: Mechanical properties table at 20 °C, range as printed (760-930 MPa)
    note: For sizes below 50 mm the datasheet gives Rm minimum 800 MPa.
    status: ground
    source: alleima-bar
    where: Mechanical properties, Tensile strength at 20 °C table, Rm
  - benchmark: ultimate_tensile_strength
    value: 750
    value_high: 930
    bound: range
    unit: MPa
    scope: material
    conditions:
      form: forgings produced from billets (ASTM A182 values valid, as footnoted)
      temper: solution annealed and quenched
      temperature: 20 °C
    method: Mechanical properties table at 20 °C, range as printed (750-930 MPa, footnote c)
    status: ground
    source: alleima-billet
    where: Mechanical properties, At 20 °C table, Rm column
  - benchmark: elongation
    value: 25
    bound: lower
    unit: '%'
    scope: material
    conditions:
      form: seamless tube and pipe, wall up to 20 mm
      temper: solution annealed and quenched
      temperature: 20 °C
      gauge: A, L0 = 5.65 times the square root of S0
    method: Mechanical properties table at 20 °C, minimum as printed (≥25)
    status: ground
    source: alleima-tube
    where: Mechanical properties, At 20 °C table, A column
  - benchmark: elongation
    value: 25
    bound: lower
    unit: '%'
    scope: material
    conditions:
      form: forgings produced from billets (ASTM A182 values valid, as footnoted)
      temper: solution annealed and quenched
      temperature: 20 °C
      gauge: A, L0 = 5.65 times the square root of S0
    method: Mechanical properties table at 20 °C, minimum as printed (≥25)
    status: ground
    source: alleima-billet
    where: Mechanical properties, At 20 °C table, A column
  - benchmark: hardness
    value: 32
    bound: upper
    unit: HRC
    scope: material
    conditions:
      form: seamless tube and pipe, wall up to 20 mm
      temper: solution annealed and quenched
      temperature: 20 °C
      basis: maximum
    method: Mechanical properties table at 20 °C, maximum as printed (≤32 HRC)
    status: ground
    source: alleima-tube
    where: Mechanical properties, At 20 °C table, Hardness HRC column
  - benchmark: hardness
    value: 28
    bound: upper
    unit: HRC
    scope: material
    conditions:
      form: bar, solution annealed and quenched
      temperature: not stated
      basis: maximum
    method: Hardness line, maximum as printed (Max. 28HRC)
    status: ground
    source: alleima-bar
    where: Hardness line, after the Impact strength section
  - benchmark: hardness
    value: 260
    bound: exact
    unit: HB
    scope: material
    conditions:
      form: forgings produced from billets (ASTM A182 values valid, as footnoted)
      temper: solution annealed and quenched
      temperature: 20 °C
      basis: approximate value as printed
    method: Mechanical properties table at 20 °C, HB column (approx. 260)
    status: ground
    source: alleima-billet
    where: Mechanical properties, At 20 °C table, HB column
  - benchmark: elastic_modulus
    value: 200
    unit: GPa
    scope: material
    conditions:
      form: seamless tube and pipe
      temper: solution annealed and quenched
      temperature: 20 °C
    method: Modulus of elasticity table, 20 °C row (printed as 200 x 10^3 MPa)
    status: ground
    source: alleima-tube
    where: Modulus of elasticity table, 20 °C row
  - benchmark: elastic_modulus
    value: 180
    unit: GPa
    scope: material
    conditions:
      form: seamless tube and pipe
      temper: solution annealed and quenched
      temperature: 300 °C
    method: Modulus of elasticity table, 300 °C row (printed as 180 x 10^3 MPa)
    status: ground
    source: alleima-tube
    where: Modulus of elasticity table, 300 °C row
  - benchmark: density
    value: 7.8
    unit: g/cm3
    scope: material
    conditions:
      form: seamless tube and pipe
      temperature: not stated
      basis: typical value as printed
    method: Physical properties section, Density line (printed 7.8 g/cm3)
    status: ground
    source: alleima-tube
    where: Physical properties section, Density line
  - benchmark: specific_heat
    value: 490
    unit: J/kg.K
    scope: material
    conditions:
      form: seamless tube and pipe
      temperature: 20 °C
    method: Specific heat capacity table, 20 °C row (printed J/kg °C)
    status: ground
    source: alleima-tube
    where: Physical properties, Specific heat capacity table, 20 °C row
  - benchmark: thermal_conductivity
    value: 14
    unit: W/m.K
    scope: material
    conditions:
      form: seamless tube and pipe
      temperature: 20 °C
    method: Thermal conductivity table, 20 °C column (printed W/m °C)
    status: ground
    source: alleima-tube
    where: Thermal conductivity table, SAF 2507 row, 20 column
  - benchmark: cte
    value: 13.5
    unit: 10-6/K
    scope: material
    conditions:
      form: seamless tube and pipe
      temperature: 30 to 100 °C mean
      unit_in_source: x10-6/°C
    method: Thermal expansion table, 30-100 °C column (printed x10-6/°C)
    note: The same table prints 16.5 for ASTM 316L and 12.5 for carbon steel over 30 to 100 °C.
    status: ground
    source: alleima-tube
    where: Thermal expansion table, 30-100 °C column
  - benchmark: electrical_resistivity
    value: 0.83
    unit: μΩm
    scope: material
    conditions:
      form: seamless tube and pipe
      temperature: 20 °C
    method: Resistivity table, 20 °C row (printed μΩm)
    status: ground
    source: alleima-tube
    where: Resistivity table, 20 °C row
  - benchmark: pren
    value: 42.5
    bound: lower
    unit: '-'
    scope: material
    conditions:
      form: seamless tube and pipe
      temperature: not stated
      basis: minimum PRE; PRE = %Cr + 3.3 x %Mo + 16 x %N
    method: Pitting and crevice corrosion section, minimum PRE stated for seamless tubes
    status: ground
    source: alleima-tube
    where: Pitting and crevice corrosion section, seamless tube minimum
  - benchmark: pren
    value: 41
    bound: lower
    unit: '-'
    scope: material
    conditions:
      form: general minimum for SAF 2507, product form not stated
      temperature: not stated
      basis: minimum PRE; PRE = %Cr + 3.3 x %Mo + 16 x %N
    method: Pitting and crevice corrosion section, minimum PRE value as printed
    status: ground
    source: alleima-bar
    where: Pitting and crevice corrosion section, minimum PRE sentence
  - benchmark: critical_crevice_temperature
    value: 64
    unit: °C
    scope: material
    conditions:
      form: seamless tube and pipe
      environment: natural seawater
      potential: 150 mV vs SCE
      step: 4 °C every 24 hours
    method: Crevice corrosion test in natural seawater, temperature raised until crevice corrosion occurred (CCT table)
    status: ground
    source: alleima-tube
    where: Crevice corrosion section, CCT table, SAF 2507 row
  - benchmark: critical_pitting_temperature
    value: 72.5
    unit: °C
    scope: material
    conditions:
      form: seamless tube and pipe
      solution: 'Green death: 1% FeCl3 + 1% CuCl2 + 11% H2SO4 + 1.2% HCl'
    method: Critical pitting temperature table, Green death column
    status: ground
    source: alleima-tube
    where: Critical pitting temperature table, Green death column
  - benchmark: critical_pitting_temperature
    value: 90
    bound: lower
    unit: °C
    scope: material
    conditions:
      form: seamless tube and pipe
      solution: 'Yellow death: 0.1% Fe2(SO4)3 + 4% NaCl + 0.01 M HCl'
    method: Critical pitting temperature table, Yellow death column (printed as >90)
    status: ground
    source: alleima-tube
    where: Critical pitting temperature table, Yellow death column
  - benchmark: critical_pitting_temperature
    value: 50
    bound: lower
    unit: °C
    scope: material
    conditions:
      test: ASTM G48 method A, 6% FeCl3
      temper: solution annealed and quenched
      form: billet and forgings
    method: Corrosion resistance section, minimum temperature at which the test is passed
    status: ground
    source: alleima-billet
    where: Corrosion resistance section, ASTM G48 sentence
  - benchmark: max_service_temp
    value: 232
    bound: upper
    unit: °C
    scope: material
    conditions:
      environment: sour oil and gas service, ISO 15156 / NACE MR 0175
      h2s: partial pressure at most 0.20 bar (3 psi)
      form: wrought, solution annealed and rapidly cooled
      hardness: max 32 HRC
    method: Sour environments paragraph, 450 °F (232 °C) as printed
    status: ground
    source: alleima-tube
    where: Sour environments paragraph
  - benchmark: embrittlement_temperature_limit
    value: 250
    bound: upper
    unit: °C
    scope: material
    conditions:
      form: seamless tube and pipe (the bar datasheet gives the same limit)
      temperature: prolonged exposure above 250 °C
      basis: microstructure change that lowers impact strength
    method: Datasheet statement at high temperatures, 250 °C (480 °F) as printed
    status: ground
    source: alleima-tube
    where: At high temperatures section
  - benchmark: impact_energy
    value: 100
    bound: lower
    unit: J
    scope: material
    conditions:
      form: bar, longitudinal Charpy V
      temper: solution annealed and quenched
      temperature: 20 °C
      basis: average; single minimum 70 J
    method: Impact strength section, room temperature guarantee (minimum 100 J average)
    status: ground
    source: alleima-bar
    where: Impact strength section, RT or 20 °C sentence
  - benchmark: impact_energy
    value: 45
    bound: lower
    unit: J
    scope: material
    conditions:
      form: bar, over 200 to 250 mm diameter, longitudinal Charpy V
      temper: solution annealed and quenched
      temperature: '-50 °C'
      basis: average; single minimum 35 J
    method: Impact strength section, guarantee at -50 °C (45 J average as printed)
    status: ground
    source: alleima-bar
    where: Impact strength section, guarantee at -50 °C
  - benchmark: impact_energy
    value: 27
    bound: lower
    unit: J
    scope: material
    conditions:
      form: gas-shielded arc weldments
      temperature: '-50 °C'
      basis: minimum as printed
    method: Impact strength section, weldment minimum at -50 °C
    status: ground
    source: alleima-tube
    where: Impact strength section, weldment sentence
corrosion:
  - environment: Natural seawater, crevice corrosion
    headline: Crevice corrosion started at 64 °C in natural seawater, against 61 °C for 6Mo+N in the same test.
    effect: Alleima raised the temperature in 4 °C steps every 24 hours at 150 mV vs SCE until crevice corrosion occurred. The table gives 64 °C for SAF 2507 and 61 °C for 6Mo+N. Propagation rates of initiated crevice attack at 15 to 50 °C were about ten times lower for SAF 2507 than for 6Mo+N.
    rating: moderate
    conditions:
      environment: natural seawater
      potential: 150 mV vs SCE
      step: 4 °C every 24 hours
      form: seamless tube and pipe
    source: alleima-tube
    where: Crevice corrosion section and CCT table (SAF 2507 row)
  - environment: Ferric chloride pitting and crevice test, ASTM G48 method A
    headline: Passes ASTM G48 method A at 50 °C or higher in the solution annealed and quenched condition.
    effect: The billet page says SAF 2507 passes the pitting and crevice test at a minimum of 50 °C. The bar datasheet shows its G48 critical temperatures only in a figure, so no bar value is used.
    rating: low
    conditions:
      test: ASTM G48 method A, 6% FeCl3
      condition: solution annealed and quenched
      form: billet and forgings
    source: alleima-billet
    where: Corrosion resistance section, ASTM G48 sentence
  - environment: Chloride stress corrosion cracking
    headline: No cracking at 1000 ppm chloride and 300 °C, or 10000 ppm chloride and 250 °C.
    effect: Alleima reports no SCC up to 1000 ppm Cl- at 300 °C and 10000 ppm Cl- at 250 °C. Parent metal and welds in boiling 45% MgCl2 at 155 °C have a threshold stress of about 50 percent of proof strength (ASTM G36). U-bend specimens in hot 25% NaCl brine at 108 °C for 1000 hours did not crack.
    rating: low
    conditions:
      chloride: 1000 ppm at 300 °C; 10000 ppm at 250 °C
      test: boiling 45% MgCl2 at 155 °C (ASTM G36)
      form: seamless tube and pipe
    source: alleima-tube
    where: Stress corrosion cracking section
  - environment: Sour oil and gas service (H2S)
    headline: Suitable up to 232 °C in sour service when the H2S partial pressure is at most 0.20 bar.
    effect: Solution annealed and rapidly cooled wrought SAF 2507 is suitable up to 232 °C (450 °F) under ISO 15156 / NACE MR 0175 if the H2S partial pressure does not exceed 0.20 bar (3 psi). Under NACE MR0103 it is suitable for sour petroleum refining at a maximum hardness of 32 HRC.
    rating: low
    conditions:
      temperature: up to 232 °C
      h2s: at most 0.20 bar (3 psi)
      hardness: max 32 HRC
      condition: solution annealed and rapidly cooled
    source: alleima-tube
    where: Sour environments paragraph
  - environment: Organic acids
    headline: Under 0.05 mm/year in 10% formic acid and 50% acetic acid, where 316L is above 0.2 mm/year.
    effect: Alleima says SAF 2507 is highly resistant to organic acids, with under 0.05 mm/year in 10% formic and 50% acetic acid, where ASTM 316L corrodes above 0.2 mm/year. Contaminated acid also leaves it resistant.
    rating: low
    conditions:
      acids: 10% formic and 50% acetic
      comparison: ASTM 316L above 0.2 mm/year
      form: seamless tube and pipe
    source: alleima-tube
    where: General corrosion section
  - environment: Intergranular attack after welding
    headline: Passes the Strauss test (ASTM A262 practice E) without reservations.
    effect: The billet page says the composition re-forms austenite quickly in the weld heat-affected zone, which gives good resistance to intergranular corrosion. SAF 2507 passes ASTM A262 Practice E (Strauss test) without reservations.
    rating: low
    conditions:
      test: ASTM A262 practice E (Strauss test)
      form: billet and forgings
    source: alleima-billet
    where: Corrosion resistance section, ASTM A262 sentence
  - environment: Erosion corrosion and corrosion fatigue
    headline: Excellent resistance, better than standard austenitic grades (qualitative only).
    effect: The bar datasheet says the mechanical strength and corrosion resistance give excellent resistance to erosion corrosion and corrosion fatigue, compared with standard austenitic grades. It prints no test numbers.
    rating: low
    conditions:
      basis: qualitative statement, no test numbers printed
    source: alleima-bar
    where: Erosion corrosion and corrosion fatigue section
  - environment: Chloride pitting (PRE index), bar datasheet
    headline: Minimum PRE of 41 for SAF 2507; UNS S31260 is typically 38.
    effect: Alleima defines PRE as %Cr + 3.3 x %Mo + 16 x %N and says it is equal in ferrite and austenite. The bar datasheet gives 41 as the minimum PRE for SAF 2507 and typically 38 for UNS S31260 (25Cr3Mo0.2N).
    rating: low
    conditions:
      formula: PRE = %Cr + 3.3 x %Mo + 16 x %N
      basis: weight percent, minimum
    source: alleima-bar
    where: Pitting and crevice corrosion section
  - environment: Chloride pitting (PRE index), tube datasheet
    headline: Minimum PRE of 42.5 for seamless tube; 25Cr3Mo0.2N is 33 at minimum.
    effect: The tube datasheet gives 42.5 as the minimum PRE for SAF 2507 seamless tubes, and 33 as the minimum for 25Cr3Mo0.2N (UNS S31260).
    rating: low
    conditions:
      formula: PRE = %Cr + 3.3 x %Mo + 16 x %N
      basis: weight percent, minimum
    source: alleima-tube
    where: Pitting and crevice corrosion section, PRE values
risks:
  hazards:
    - text: PubChem's aggregated GHS list for elemental nickel gives H317, H351, H372 and H412, with signal word Danger. PubChem also says 0.1 percent of 4,778 company reports do not meet GHS criteria. These cover the element, not the alloy.
      ghs:
        - H317
        - H351
        - H372
        - H412
      source: pubchem-nickel
      where: GHS Classification, Hazard Statements (CID 935)
    - text: PubChem notes for elemental chromium include H317, H319 and H334, with signal word Danger. 50 percent of 2,404 company reports say the element does not meet GHS hazard criteria.
      ghs:
        - H317
        - H319
        - H334
      source: pubchem-chromium
      where: GHS Classification, Hazard Statements (CID 23976)
    - text: PubChem notes for elemental molybdenum include H315, H319 and H335, with signal word Warning. 57.4 percent of 1,523 company reports say the element does not meet GHS hazard criteria.
      ghs:
        - H315
        - H319
        - H335
      source: pubchem-molybdenum
      where: GHS Classification, Hazard Statements (CID 23932)
  failure_risks:
    - mode: Crevice and pitting attack in hot chloride seawater
      trigger: Chloride seawater or process fluid in crevices, at temperatures above the crevice test result
      consequence: Alleima's natural seawater test gave crevice corrosion at 64 °C at 150 mV vs SCE, so crevices are a design limit at warm temperatures
      severity: moderate
      source: alleima-tube
      where: Crevice corrosion section and CCT table
    - mode: Loss of impact strength after prolonged exposure above 250 °C
      trigger: Prolonged service above 250 °C
      consequence: The microstructure changes and impact strength falls. Alleima says this may not change behaviour at the operating temperature.
      severity: moderate
      source: alleima-bar
      where: Impact strength section, At higher temperatures
    - mode: Hydrogen-induced stress cracking on cathodically protected subsea steel
      trigger: High tensile stress on subsea steel under cathodic protection, with coarse austenite spacing
      consequence: Hydrogen diffuses fastest in ferrite, so cracks run in the ferrite phase. Alleima says the risk falls when austenite spacing is under 30 µm (DNV RP-F112). Cold-pilgered, solution-annealed tubes with 5 to 15 µm spacing resisted cracking at 130 percent of yield.
      severity: high
      source: alleima-tube
      where: Hydrogen Induced Stress Cracking section
    - mode: Sour service outside the stated limits
      trigger: H2S partial pressure above 0.20 bar (3 psi), temperature above 232 °C, or hardness above 32 HRC
      consequence: Outside those limits Alleima gives no suitability statement for sour oil and gas service
      severity: moderate
      source: alleima-tube
      where: Sour environments paragraph
  side_effects: []
  handling:
    - text: Bending needs a slightly higher starting force than ASTM 304L or 316L. If service is near the stress-corrosion limit, heat treat after cold bending (tube datasheet).
      source: alleima-tube
      where: Fabrication, Bending section
    - text: Expanding into tubesheets needs more initial force and should be done in one operation. Weld tube-to-tubesheet joints where chloride is high (tube datasheet).
      source: alleima-tube
      where: Fabrication, Expanding section
    - text: TIG is the first choice for welding. Use 0.2 to 1.5 kJ/mm heat input, keep the interpass under 150 °C, and do not preheat. Post-weld heat treatment is normally not needed (bar datasheet).
      source: alleima-bar
      where: Welding section
    - text: Recommended filler metals are of the 25.10.4.L type, such as ISO 14343 S 25 9 4 N L or AWS A5.9 ER2594 (bar datasheet).
      source: alleima-bar
      where: Welding section, recommended filler metals
    - text: 'Machining is harder than for austenitic grades: difficult chip control, high cutting forces and tool wear (bar datasheet).'
      source: alleima-bar
      where: Machining section
    - text: Hot bending is carried out at 1125 to 1025 °C, followed by solution annealing (tube datasheet).
      source: alleima-tube
      where: Fabrication, Bending section
  mitigations:
    - text: Solution anneal at 1050 to 1125 °C and quench in air or water. This restores the microstructure free of grain-boundary carbides and intermetallic phases (bar and tube datasheets).
      source: alleima-bar
      where: Heat Treatment and Microstructure sections
    - text: Keep prolonged service at or below 250 °C. For pressure vessels the maximum is 250 °C under VdTÜV-Wb 508 and NGS 1609 (tube datasheet).
      source: alleima-tube
      where: At high temperatures section
    - text: Keep austenite spacing under 30 µm for resistance to hydrogen-induced cracking under cathodic protection, as DNV RP-F112 recommends (tube datasheet).
      source: alleima-tube
      where: Hydrogen Induced Stress Cracking section
    - text: For sour service, specify solution-annealed, rapidly cooled wrought material with hardness at most 32 HRC (tube datasheet).
      source: alleima-tube
      where: Sour environments paragraph
uses:
  - application: structures
    device: Subsea umbilicals and offshore oil and gas tubing
    example: Alleima lists hydraulic and process fluid tubes in umbilicals, and chloride-containing seawater handling and process systems, for oil and gas exploration and production.
    source: alleima-tube
    where: Typical applications for SAF 2507 table, oil and gas row
  - application: structures
    device: Seawater cooling tubing and desalination pressure vessels
    example: Alleima lists heat-exchanger tubing that uses seawater or chlorinated seawater as coolant, pressure vessels for reverse osmosis units, and tube and pipe for seawater transport.
    source: alleima-tube
    where: Typical applications for SAF 2507 table, seawater cooling and desalination rows
  - application: mechanisms
    device: Propeller shafts and high-load parts in seawater
    example: Alleima lists propeller shafts and other products under high mechanical load in seawater and other chloride-containing environments.
    source: alleima-tube
    where: Typical applications for SAF 2507 table, mechanical components row
  - application: structures
    device: Forged flanges and fittings to ASTM A182 Grade F53
    example: The billet page says billets are suitable for further production to ASTM A182 Grade F53. The tube datasheet lists flanges and fittings to ASTM A182.
    source: alleima-billet
    where: Forging billets section, ASTM A182 Grade F53 sentence
supply:
  - subject: Nickel
    abundance: World mine production 3,900,000 metric tons of nickel content in 2025 (estimated), with reserves above 140,000,000 tons. Stainless and alloy steel plus nickel-containing alloys take more than 85 percent of US consumption. US net import reliance was 41 percent in 2025 (estimated).
    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: New Caledonia
        share_percent: 3.6
        year: 2025
      - country: Canada
        share_percent: 3.6
        year: 2025
      - country: China
        share_percent: 3.1
        year: 2025
    critical_lists: []
    recycling: Nickel recovered from scrap was about 60 percent of US apparent consumption in 2025. Most secondary nickel is stainless-steel scrap.
    substitutes:
      - Low-nickel, duplex or ultrahigh-chromium stainless steels have been substituted for austenitic grades in construction (USGS 2026).
      - Titanium alloys can substitute for nickel or nickel-base alloys in corrosive environments (USGS 2026).
    source: usgs-nickel-2026
    where: World Mine Production and Reserves table (2025e, nickel content); Salient Statistics; Recycling; Substitutes
  - subject: Chromium
    abundance: World mine production about 51,000 thousand metric tons of ore, gross weight, in 2025 (estimated). World resources are greater than 12 billion tons of shipping-grade chromite, 95 percent in Kazakhstan and southern Africa. US net import reliance was 79 percent in 2025 (estimated). Chromite imports for 2021 to 2024 came 96 percent from South Africa.
    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: Brazil
        share_percent: 3.9
        year: 2025
      - country: Zimbabwe
        share_percent: 3.9
        year: 2025
    critical_lists: []
    recycling: Recycled chromium in stainless-steel scrap receipts was 21 percent of US apparent consumption in 2025.
    substitutes:
      - Chromium has no substitute in stainless steel, the leading end use (USGS 2026).
    source: usgs-chromium-2026
    where: World Mine Production and Reserves table (2025e, gross weight); World Resources; Salient Statistics; Import Sources (2021-24); Recycling; Substitutes
  - subject: Molybdenum
    abundance: World mine production 260,000 metric tons of molybdenum content in 2025 (estimated). China, Chile, the United States, Peru and Mexico produce 90 percent of the total. China imposed export controls on molybdenum powders in February 2025. The United States is a net exporter.
    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: Molybdenum in new and old steel and other scrap may be as much as 30 percent of apparent supply (USGS 2026).
    substitutes:
      - There is little substitution for molybdenum in steels. Potential substitutes include boron, chromium, niobium and vanadium (USGS 2026).
    source: usgs-molybdenum-2026
    where: World Mine Production and Reserves table (2025e, molybdenum content); Events, Trends, and Issues; Recycling; Substitutes
media: []
documents:
  - title: 'Alleima: SAF 2507 bar datasheet (UNS S32750, EN 1.4410)'
    type: datasheet
    url: https://www.alleima.com/en/technical-center/material-datasheets/bar-and-hollow-bar/bar/saf-2507/?show=pdf
    year: 2026
  - title: 'Alleima: SAF 2507 seamless tube and pipe datasheet'
    type: datasheet
    url: https://www.alleima.com/en/technical-center/material-datasheets/tube-and-pipe-seamless/saf-2507/?show=pdf
    year: 2026
  - title: 'Alleima: SAF 2507 forging billets (ASTM A182 Grade F53 sentence, billet mechanical and physical data)'
    type: datasheet
    url: https://alleima.com/en/technical-center/material-datasheets/billets/saf-2507
  - 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: Nickel (CID 935), GHS classification'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/935/JSON
    year: 2026
  - title: 'PubChem: Chromium (CID 23976), GHS classification'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23976/JSON
    year: 2026
  - title: 'PubChem: Molybdenum (CID 23932), GHS classification'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23932/JSON
    year: 2026
gaps:
  - Melting range, Poisson's ratio, shear modulus and bulk modulus are not printed in the fetched Alleima datasheets, the Wikipedia article or the USGS pages, so they are not given.
  - The Alleima bar datasheet shows its ASTM G48 critical temperatures only in a figure, so no bar value is used. The crevice and pitting values come from the tube datasheet tables and the billet sentence.
  - No Outokumpu 2507 datasheet was opened because the ULProspector page needs an account. Alleima is the only manufacturer datasheet source for this profile.
  - 'Values are given per product form: seamless tube and pipe (walls up to 20 mm), bar, and billet forgings (ASTM A182 values as footnoted). No value is given for forgings above the bar range.'
  - Fatigue strength and corrosion-fatigue values are printed only as figures in the datasheets, so none is recorded.
  - The 475 °C embrittlement window and sigma-phase data are not in any fetched source for this profile. The only limit recorded is Alleima's 250 °C prolonged-exposure statement.
  - Hardness, PRE, critical crevice and pitting temperatures, the embrittlement limit and impact energy are not canonical property names. Short snake_case names are used for them.
  - No safety data sheet for the alloy was read. Hazard data are PubChem element records for nickel, chromium and molybdenum. Single-notification entries in those records were not used.
  - 'critical_lists are empty: the USGS 2025 critical-minerals list and the EU critical raw materials list were not read in this run.'
  - Supply shares are mine production only, not refining or smelting, and are calculated from the printed tonnages.
  - The AZoM 2507 page is a supplier listing with no property values, so it is not cited.
sources:
  alleima-bar:
    title: 'Alleima: SAF 2507 bar datasheet (UNS S32750, EN 1.4410)'
    id: SAF 2507 bar, last updated 23 Feb 2026
    url: https://www.alleima.com/en/technical-center/material-datasheets/bar-and-hollow-bar/bar/saf-2507/?show=pdf
    kind: datasheet
    year: 2026
    license: cited, not reproduced
  alleima-tube:
    title: 'Alleima: SAF 2507 seamless tube and pipe datasheet'
    id: SAF 2507 tube and pipe, last updated 16 Feb 2026
    url: https://www.alleima.com/en/technical-center/material-datasheets/tube-and-pipe-seamless/saf-2507/?show=pdf
    kind: datasheet
    year: 2026
    license: cited, not reproduced
  alleima-billet:
    title: 'Alleima: SAF 2507 forging billets (ASTM A182 Grade F53)'
    id: SAF 2507 billets
    url: https://alleima.com/en/technical-center/material-datasheets/billets/saf-2507
    kind: datasheet
    license: cited, not reproduced
  wiki-saf2507:
    title: 'Wikipedia: SAF 2507'
    id: SAF 2507
    url: https://en.wikipedia.org/wiki/SAF_2507
    kind: web
    license: CC BY-SA 4.0 (cited, not reproduced)
  usgs-nickel-2026:
    title: 'USGS Mineral Commodity Summaries 2026: Nickel'
    id: mcs2026-nickel
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf
    kind: report
    year: 2026
    license: public domain
  usgs-chromium-2026:
    title: 'USGS Mineral Commodity Summaries 2026: Chromium'
    id: mcs2026-chromium
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-chromium.pdf
    kind: report
    year: 2026
    license: public domain
  usgs-molybdenum-2026:
    title: 'USGS Mineral Commodity Summaries 2026: Molybdenum'
    id: mcs2026-molybdenum
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-molybdenum.pdf
    kind: report
    year: 2026
    license: public domain
  pubchem-nickel:
    title: 'PubChem: Nickel (CID 935), GHS classification'
    id: CID 935
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/935/JSON
    kind: database
    license: PubChem terms (public)
  pubchem-chromium:
    title: 'PubChem: Chromium (CID 23976), GHS classification'
    id: CID 23976
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23976/JSON
    kind: database
    license: PubChem terms (public)
  pubchem-molybdenum:
    title: 'PubChem: Molybdenum (CID 23932), GHS classification'
    id: CID 23932
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23932/JSON
    kind: database
    license: PubChem terms (public)
license: CC-BY-4.0
updated: '2026-10-24'
review:
  status: draft
  method: assistant
  checked_values: 30
  unreachable: 0
  caveats: 3
  note: 'Read by an AI assistant on 2026-10-24 from pages fetched in this run: Alleima SAF 2507 bar datasheet (updated 23 Feb 2026), Alleima SAF 2507 seamless tube and pipe datasheet (updated 16 Feb 2026), Alleima SAF 2507 forging billet page (ASTM A182 Grade F53 values), Wikipedia SAF 2507, USGS Mineral Commodity Summaries 2026 for nickel, chromium and molybdenum, and PubChem GHS records for nickel, chromium and molybdenum. Each value carries its product form and temperature in conditions.'
story:
  why: SAF 2507 is a super duplex stainless steel made for chloride-bearing service. Its mix of ferrite and austenite, with about 25 percent chromium, 4 percent molybdenum and 0.3 percent nitrogen, gives a minimum pitting resistance equivalent of 41 in bar and 42.5 in seamless tube. Its minimum proof strength is 550 MPa, and Alleima says its proof and tensile strength are higher than those of austenitic grades. It is sold for seawater cooling, subsea umbilicals and desalination equipment. Its main limits are long exposure above 250 °C, which lowers impact strength, and hydrogen cracking in cathodically protected subsea steel.
  uses:
    - where: Offshore and subsea
      line: Alleima lists hydraulic and process fluid tubes in umbilicals, and seawater handling and process systems, for oil and gas production.
    - where: Seawater cooling and desalination
      line: Alleima lists heat-exchanger tubing that uses seawater as coolant, pressure vessels for reverse osmosis units, and tube and pipe for seawater transport.
    - where: Propeller shafts
      line: Alleima lists propeller shafts and other high-load parts in seawater and chloride environments.
    - where: Flanges and fittings to ASTM A182 Grade F53
      line: The billet page says billets are suited to further production to ASTM A182 Grade F53. The tube datasheet lists flanges and fittings to ASTM A182.
  can_do:
    - label: Strength
      benchmark: yield_strength
      line: Minimum proof strength is 550 MPa in the tube datasheet at 20 °C. Tensile strength is 800 to 1000 MPa for tube and 760 to 930 MPa for bar.
    - label: Pitting
      benchmark: pren
      line: Minimum PRE is 41 in the bar datasheet and 42.5 in seamless tube. UNS S31260 is typically 38.
    - label: Seawater crevices
      benchmark: critical_crevice_temperature
      line: In Alleima's natural seawater test, crevice corrosion starts at 64 °C, against 61 °C for 6Mo+N.
    - label: Cold toughness
      benchmark: impact_energy
      line: The bar datasheet guarantees 45 J average at -50 °C for large sizes, with 35 J as the single minimum.
  compare: Against UNS S31260, the 25 percent chromium duplex that Alleima gives a typical PRE of 38 (bar) and a minimum of 33 (tube), SAF 2507 has a minimum PRE of 41 in bar and 42.5 in tube. Against austenitic grades, Alleima says its proof and tensile strength are higher. Its thermal expansion is 13.5 over 30 to 100 °C, against 16.5 for ASTM 316L and 12.5 for carbon steel in the same table. In Alleima's natural seawater test its crevice corrosion temperature is 64 °C, against 61 °C for 6Mo+N.
  compare_rows:
    - label: Proof strength (Rp0.2)
      benchmark: yield_strength
    - label: Tensile strength (Rm)
      benchmark: ultimate_tensile_strength
    - label: Pitting resistance (PRE)
      benchmark: pren
  handling:
    - Weld with TIG first, at 0.2 to 1.5 kJ/mm heat input, an interpass limit of 150 °C and no preheat (bar datasheet).
    - Solution anneal at 1050 to 1125 °C and quench if further processing needs heat treatment (tube datasheet).
    - 'Machining is harder than for austenitic grades: chip control, cutting force and tool wear all need dedicated tools (bar datasheet).'
  good_for:
    - Seawater cooling, desalination and chloride process plant, where Alleima lists tube, pipe and pressure vessels.
    - Subsea and offshore hydraulic and process tubing in umbilicals, and propeller shafts in seawater.
    - Sour oil and gas service up to 232 °C where H2S is at most 0.20 bar and hardness is at most 32 HRC.
  watch_out:
    - Prolonged exposure above 250 °C lowers impact strength. The pressure-vessel limit in the datasheet is 250 °C.
    - Cathodically protected subsea steel can crack from hydrogen under high tensile stress. The datasheet says the risk falls when austenite spacing is under 30 µm.
    - Crevice attack in seawater starts at 64 °C under Alleima's test conditions, so crevice design still matters in warm service.
    - No safety data sheet for the alloy was read. The hazard data are PubChem records for its elements, not supplier classifications.
  verdict: SAF 2507 is a strong, chloride-resistant duplex choice for seawater, subsea and sour oil and gas parts. Keep prolonged temperatures under 250 °C, and design out crevices and hydrogen-cracking risk under cathodic protection.
  recipe:
    line: SAF 2507 is an iron-based duplex stainless steel. Its nominal recipe, in weight percent, is 25 chromium, 7 nickel, 4 molybdenum and 0.3 nitrogen, with iron as the balance. Carbon, manganese, silicon, phosphorus, sulfur and copper are held to the maxima in the datasheet table. Solution annealing at 1050 to 1125 °C and quenching gives 35 to 55 percent ferrite.
    parts:
      - name: Iron
        symbol: Fe
        share_note: balance
        role: Matrix of the alloy, shared between ferrite and austenite.
      - name: Chromium
        symbol: Cr
        share_percent: 25
        role: Forms the passive film. With molybdenum and nitrogen it sets the PRE.
        source: alleima-bar
        where: Chemical composition (nominal) table
      - name: Nickel
        symbol: Ni
        share_percent: 7
        role: Stabilises austenite, balancing the two phases.
        source: alleima-bar
        where: Chemical composition (nominal) table
      - name: Molybdenum
        symbol: Mo
        share_percent: 4
        role: Adds pitting and crevice resistance; weighted 3.3 in the PRE formula.
        source: alleima-bar
        where: Chemical composition (nominal) table
      - name: Nitrogen
        symbol: 'N'
        share_percent: 0.3
        role: Adds strength and stabilises austenite; weighted 16 in the PRE formula.
        source: alleima-bar
        where: Chemical composition (nominal) table
      - name: Carbon
        symbol: C
        share_note: max 0.03
        role: Kept low to limit chromium carbides at grain boundaries.
        source: alleima-bar
        where: Chemical composition (nominal) table
      - name: Manganese
        symbol: Mn
        share_note: max 1.2
        role: Deoxidiser and austenite former in the melt.
        source: alleima-bar
        where: Chemical composition (nominal) table
      - name: Silicon
        symbol: Si
        share_note: max 0.8
        role: Deoxidiser in the melt.
        source: alleima-bar
        where: Chemical composition (nominal) table
      - name: Phosphorus
        symbol: P
        share_note: max 0.035
        role: Impurity held low.
        source: alleima-bar
        where: Chemical composition (nominal) table
      - name: Sulfur
        symbol: S
        share_note: max 0.015
        role: Impurity held low.
        source: alleima-bar
        where: Chemical composition (nominal) table
      - name: Copper
        symbol: Cu
        share_note: max 0.5
        role: Impurity held low.
        source: alleima-bar
        where: Chemical composition (nominal) table
  risk_groups:
    - title: For people
      level: 0
      verdict: No safety data sheet read for the alloy
      lead: The hazard data are PubChem records for the three main elements. They are aggregated notifications, not a supplier classification.
      points:
        - label: Nickel
          line: PubChem's aggregated GHS list for elemental nickel gives H317, H351, H372 and H412, with signal word Danger.
        - label: Chromium
          line: PubChem notes for elemental chromium include H317, H319 and H334, with signal word Danger.
        - label: Molybdenum
          line: PubChem notes for elemental molybdenum include H315, H319 and H335, with signal word Warning.
    - title: In seawater
      level: 1
      verdict: Chloride crevices are the watch point
      lead: Crevice and pitting attack are the main failure routes in seawater. Hydrogen cracking is the main risk on cathodically protected subsea steel.
      points:
        - label: Crevice
          line: Alleima's natural seawater test (150 mV vs SCE, 4 °C steps every 24 hours) gave crevice corrosion at 64 °C.
        - label: Hydrogen
          line: Hydrogen-induced cracking can occur in cathodically protected subsea steel under high tensile stress. Cracks run in the ferrite. The datasheet says the risk falls when austenite spacing is under 30 µm.
    - title: Hot service
      level: 1
      verdict: Long exposure above 250 °C lowers toughness
      lead: The change is in the microstructure. Alleima says it may not change how the material behaves at its operating temperature.
      points:
        - label: Limit
          line: The datasheet gives 250 °C as the prolonged-exposure limit and as the pressure-vessel maximum under VdTÜV-Wb 508 and NGS 1609.
        - label: Sour service
          line: Sour oil and gas service is allowed up to 232 °C when H2S is at most 0.20 bar (3 psi) and hardness is at most 32 HRC.
    - title: Fabrication
      level: 0
      verdict: Controlled heat input is enough
      lead: Weldability is good. Heat input, bending and tube expansion each need care.
      points:
        - label: Welding
          line: Use 0.2 to 1.5 kJ/mm heat input, keep the interpass below 150 °C, and avoid preheat (bar datasheet).
        - label: Bending
          line: Hot bending at 1125 to 1025 °C, followed by solution annealing (tube datasheet).