spore: profile
id: stainless-2205
spore_version: '0.2'
family: stainless-duplex
name: Duplex stainless steel 2205
abbreviation: 2205 (UNS S32205)
role: structural alloy
category: metals
type: steels-and-stainless
summary: Duplex 2205 is an austenite-ferrite stainless steel with 22 to 23 percent chromium, 3.0 to 3.5 percent molybdenum and 0.14 to 0.20 percent nitrogen (ASTM A240, UNS S32205). ATI gives a typical PREN of 35.8, and the minimum 0.2 percent proof strength for plate is 450 MPa (ATI, ICAST). It resists chloride stress corrosion cracking substantially better than 300-series steels, but ATI says the 343 to 530 C range must be avoided in fabrication and service.
best_for: Chloride-bearing and sour service where 300-series steels crack, in welded pipe, tube, sheet and plate (ATI, Alleima)
weakest_at: Extended exposure at 343 to 530 C (475 C embrittlement), welds made with straight chromium filler, and sour service above 232 C (ATI, Alleima)
identity:
  formula: Fe balance, 22.0 to 23.0 Cr, 4.5 to 6.5 Ni, 3.0 to 3.5 Mo, 0.14 to 0.20 N, max 0.030 C, max 2.0 Mn, max 1.0 Si, max 0.030 P, max 0.020 S (wt%, ASTM A240 UNS S32205)
  source: icast-s32205
  where: Chemical Composition table (ASTM A240 UNS S32205)
  designations:
    - system: UNS
      code: S32205
    - system: UNS
      code: S31803
    - system: EN
      code: '1.4462'
    - system: EN name
      code: X2CrNiMoN 22-5-3
    - system: DIN
      code: X2CrNiMoN 22 5 3
    - system: SS
      code: '2377'
    - system: AFNOR
      code: Z2.CND22.05.03
    - system: ASTM
      code: A240
      note: plate, sheet and strip
    - system: ASME
      code: SA-240
      note: plate, sheet and strip
    - system: ASTM
      code: A790
      note: seamless and welded pipe
    - system: ASTM
      code: A789
      note: seamless and welded tube
    - system: EN
      code: 10216-5
      note: seamless tube
    - system: Name
      code: NFA 49-217
      note: seamless tube
    - system: ASTM
      code: A815
      note: fittings
    - system: ASTM
      code: A276
      note: bar and shapes
    - system: ASTM
      code: A479
      note: bar
    - system: EN
      code: 10088-2
      note: plate, sheet and strip
    - system: EN
      code: 10088-3
      note: bar, shapes and forged billets
    - system: Name
      code: SAF 2205
      note: Alleima
    - system: Name
      code: ATI 2205
      note: ATI
    - system: Name
      code: Alloy 2205
      note: Langley
    - system: Name
      code: 2205 Duplex
      note: Rolled Alloys
tags:
  environments: []
  stresses: []
  applications:
    - structures
    - mechanisms
properties:
  - benchmark: density
    value: 7.82
    unit: g/cm3
    scope: material
    conditions:
      form: plate, sheet and strip (ASTM A240, UNS S32205)
      heat_treatment: not printed on the page
      temperature: not printed
    method: Product table, printed as 0.283 lb/in3 and 7.82 g/cm3 (same for plate, sheet and strip)
    status: ground
    source: ati-product
    where: Plate, Sheet and Strip product tables (Density row)
  - benchmark: density
    value: 7.8
    unit: g/cm3
    scope: material
    conditions:
      form: seamless tube and pipe (SAF 2205 datasheet)
      heat_treatment: not printed
      temperature: not printed
    method: Physical properties section, printed as 7.8 g/cm3 and 0.28 lb/in3
    status: ground
    source: alleima-saf2205-pdf
    where: Physical properties section (density line)
  - benchmark: elastic_modulus
    value: 200
    unit: GPa
    scope: material
    conditions:
      form: seamless tube and pipe (SAF 2205 datasheet)
      heat_treatment: not printed
      temperature: 20 C
    method: Modulus of elasticity table, printed as 200 (x10^3 MPa) and 29.0 ksi at 20 C
    status: ground
    source: alleima-saf2205-pdf
    where: Physical properties, Modulus of elasticity table (20 C row)
  - benchmark: elastic_modulus
    value: 180
    unit: GPa
    scope: material
    conditions:
      form: seamless tube and pipe (SAF 2205 datasheet)
      heat_treatment: not printed
      temperature: 300 C
    method: Modulus of elasticity table, 300 C row printed as 180 (x10^3 MPa) and 26.2 ksi at 600 F
    status: ground
    source: alleima-saf2205-pdf
    where: Physical properties, Modulus of elasticity table (300 C row)
  - benchmark: elastic_modulus
    value: 190
    unit: kN/mm2
    scope: material
    conditions:
      form: not stated
      heat_treatment: not stated
      temperature: not stated
    method: Physical properties block, Young's Modulus printed as 190 kN/mm2
    status: ground
    source: langley-2205
    where: Physical Properties block (Young's Modulus row)
    note: Differs from Alleima 200 GPa at 20 C; both kept, not averaged
  - benchmark: poissons_ratio
    value: 0.3
    unit: '-'
    scope: material
    conditions:
      form: not stated
      heat_treatment: not stated
      temperature: not stated
    method: Physical properties table, Poisson Ratio row printed as 0.3
    status: ground
    source: rolled-2205
    where: Physical Properties table (Poisson Ratio row)
  - benchmark: thermal_conductivity
    value: 14
    unit: W/(m °C)
    scope: material
    conditions:
      form: seamless tube and pipe (SAF 2205 datasheet)
      heat_treatment: not printed
      temperature: 20 C
    method: Thermal conductivity table, metric units, SAF 2205 row, 20 C column
    status: ground
    source: alleima-saf2205-pdf
    where: Thermal conductivity table (metric, SAF 2205 row, 20 C column)
  - benchmark: thermal_conductivity
    value: 15
    unit: W/m.K
    scope: material
    conditions:
      form: not stated
      heat_treatment: not stated
      temperature: 20 C
    method: Physical properties block, printed as 15 W/m.K at 20 C
    status: ground
    source: langley-2205
    where: Physical Properties block (Thermal conductivity row)
    note: Differs from Alleima 14 W/(m °C) at 20 C; both kept, not averaged
  - benchmark: cte
    value: 13
    unit: 10-6/K
    scope: material
    conditions:
      form: seamless tube and pipe (SAF 2205 datasheet)
      heat_treatment: not printed
      temperature: 30 to 100 C mean
      unit_in_source: X10-6 per C (mean over the range)
    method: Thermal expansion table, metric units, SAF 2205 row, 30-100 C column, printed as 13.0 (X10-6 per C)
    status: ground
    source: alleima-saf2205-pdf
    where: Thermal expansion table (metric, SAF 2205 row, 30-100 C column)
  - benchmark: cte
    value: 11
    unit: 10-6/K
    scope: material
    conditions:
      form: not stated
      heat_treatment: not stated
      temperature: 20 to 300 C mean
      unit_in_source: 10-6 m/m/C
    method: Physical properties block, mean coefficient printed as 11 x 10-6 m/m/C for 20 to 300 C
    status: ground
    source: langley-2205
    where: Physical Properties block (Mean coefficient of thermal expansion row)
    note: Temperature range differs from Alleima 13.0 for 30 to 100 C; both kept
  - benchmark: specific_heat
    value: 480
    unit: J/(kg °C)
    scope: material
    conditions:
      form: seamless tube and pipe (SAF 2205 datasheet)
      heat_treatment: not printed
      temperature: 20 C
    method: Specific heat capacity table, printed as 480 J/(kg °C) at 20 C
    status: ground
    source: alleima-saf2205-pdf
    where: Specific heat capacity table (20 C row)
  - benchmark: specific_heat
    value: 400
    unit: J/kg.K
    scope: material
    conditions:
      form: not stated
      heat_treatment: not stated
      temperature: 20 C
    method: Physical properties block, printed as 400 J/kg.K at 20 C
    status: ground
    source: langley-2205
    where: Physical Properties block (Specific Heat row)
    note: Differs from Alleima 480 J/(kg °C) at 20 C; both kept, not averaged
  - benchmark: electrical_resistivity
    value: 0.74
    unit: 10-6 ohm.m
    scope: material
    conditions:
      form: seamless tube and pipe (SAF 2205 datasheet)
      heat_treatment: not printed
      temperature: 20 C
      unit_in_source: micro-ohm m, printed as μΩm
    method: Resistivity table, printed as 0.74 μΩm at 20 C
    status: ground
    source: alleima-saf2205-pdf
    where: Resistivity table (20 C row)
  - benchmark: electrical_resistivity
    value: 0.85
    unit: 10-6 ohm.m
    scope: material
    conditions:
      form: not stated
      heat_treatment: not stated
      temperature: 20 C
      unit_in_source: µΩ.m
    method: Physical properties block, Specific Electrical Resistance printed as 0.85 µΩ.m at 20 C
    status: ground
    source: langley-2205
    where: Physical Properties block (Specific Electrical Resistance row)
    note: Differs from Alleima 0.74 at 20 C; both kept, not averaged
  - benchmark: melting_point
    value: 2525
    value_high: 2625
    bound: range
    unit: °F
    scope: material
    conditions:
      form: not stated
      heat_treatment: not stated
      temperature: melting range
      unit_in_source: °F, printed as 2525 - 2625
    method: Physical properties table, Melting Range row, printed in °F only (2525 - 2625 F)
    status: ground
    source: rolled-2205
    where: Physical Properties table (Melting Range row)
    note: Printed in imperial units only; converted to °C on import
  - benchmark: yield_strength
    value: 450
    unit: MPa
    scope: material
    bound: lower
    conditions:
      form: plate, sheet and strip (ASTM A240, UNS S32205)
      heat_treatment: not printed on the page
      temperature: not printed
    method: Product table, minimum printed as 65 ksi min and 450 MPa min
    status: ground
    source: ati-product
    where: Plate, Sheet and Strip product tables (Yield Strength row)
  - benchmark: yield_strength
    value: 450
    unit: MPa
    scope: material
    bound: lower
    conditions:
      form: plate, sheet and strip (ASTM A240, UNS S32205)
      heat_treatment: solution annealing (ICAST heat treatment column)
      temperature: not printed
    method: Mechanical properties table, Yield Strength in MPa, minimum 450
    status: ground
    source: icast-s32205
    where: Mechanical Properties table (Yield Strength row)
  - benchmark: yield_strength
    value: 485
    unit: MPa
    scope: material
    bound: lower
    conditions:
      form: seamless tube and pipe, wall up to 20 mm
      heat_treatment: solution annealed
      temperature: 20 C
    method: Mechanical properties table at 20 C, Rp0.2 printed as min 485 MPa (wall above 20 mm may be slightly lower)
    status: ground
    source: alleima-saf2205-pdf
    where: Mechanical properties, 20 C table (Rp0.2 column)
  - benchmark: yield_strength
    value: 895
    unit: MPa
    scope: material
    bound: lower
    conditions:
      form: seamless tube and pipe, cold worked for oil and gas production
      heat_treatment: cold worked, no subsequent heat treatment
      temperature: not printed
    method: Cold-worked seamless tube table, Rp0.2 printed as min 895 MPa (130 ksi)
    status: ground
    source: alleima-saf2205-pdf
    where: Mechanical properties, cold-worked seamless tube and pipe table
  - benchmark: yield_strength
    value: 280
    unit: MPa
    scope: material
    bound: lower
    conditions:
      form: seamless tube and pipe, wall up to 20 mm
      heat_treatment: solution annealed (mechanical properties section)
      temperature: 300 C
    method: Proof strength table versus temperature, minimum Rp0.2 at 300 C, metric units
    status: ground
    source: alleima-saf2205-pdf
    where: At high temperatures, proof strength table (300 C row)
  - benchmark: yield_strength
    value: 48.5
    unit: ksi
    scope: material
    bound: lower
    conditions:
      form: plate (Rolled Alloys minimum elevated tensile table)
      heat_treatment: not printed
      temperature: 302 F (150 C)
    method: Minimum elevated tensile properties, plate, 0.2 percent yield at 302 F printed as 48.5 ksi
    status: ground
    source: rolled-2205
    where: Minimum Elevated Tensile Properties, Plate table (302 F row)
  - benchmark: ultimate_tensile_strength
    value: 655
    unit: MPa
    scope: material
    bound: lower
    conditions:
      form: plate, sheet and strip (ASTM A240, UNS S32205)
      heat_treatment: not printed on the page
      temperature: not printed
    method: Product table, minimum printed as 95 ksi min and 655 MPa min
    status: ground
    source: ati-product
    where: Plate, Sheet and Strip product tables (Tensile Strength row)
  - benchmark: ultimate_tensile_strength
    value: 655
    unit: MPa
    scope: material
    bound: lower
    conditions:
      form: plate, sheet and strip (ASTM A240, UNS S32205)
      heat_treatment: solution annealing (ICAST heat treatment column)
      temperature: not printed
    method: Mechanical properties table, Tensile Strength in MPa, minimum 655
    status: ground
    source: icast-s32205
    where: Mechanical Properties table (Tensile Strength row)
  - benchmark: ultimate_tensile_strength
    value: 680
    value_high: 880
    bound: range
    unit: MPa
    scope: material
    conditions:
      form: seamless tube and pipe, wall up to 20 mm
      heat_treatment: solution annealed
      temperature: 20 C
    method: Mechanical properties table at 20 C, Rm printed as 680-880 MPa
    status: ground
    source: alleima-saf2205-pdf
    where: Mechanical properties, 20 C table (Rm column)
  - benchmark: ultimate_tensile_strength
    value: 965
    unit: MPa
    scope: material
    bound: lower
    conditions:
      form: seamless tube and pipe, cold worked for oil and gas production
      heat_treatment: cold worked, no subsequent heat treatment
      temperature: not printed
    method: Cold-worked seamless tube table, Rm printed as min 965 MPa (140 ksi)
    status: ground
    source: alleima-saf2205-pdf
    where: Mechanical properties, cold-worked seamless tube and pipe table
  - benchmark: elongation
    value: 25
    unit: '%'
    scope: material
    bound: lower
    conditions:
      form: plate, sheet and strip (ASTM A240, UNS S32205)
      heat_treatment: not printed on the page
      temperature: not printed
    method: Product table, minimum printed as 25% min
    status: ground
    source: ati-product
    where: Plate, Sheet and Strip product tables (Elongation row)
  - benchmark: hardness
    value: 293
    unit: HB
    scope: material
    bound: upper
    conditions:
      form: plate, sheet and strip (ASTM A240, UNS S32205)
      heat_treatment: solution annealing (ICAST heat treatment column)
      temperature: not printed
    method: Mechanical properties table, Hardness in BHN 293 max
    status: ground
    source: icast-s32205
    where: Mechanical Properties table (Hardness row)
  - benchmark: hardness
    value: 31
    unit: HRC
    scope: material
    bound: upper
    conditions:
      form: plate, sheet and strip (ASTM A240, UNS S32205)
      heat_treatment: not printed on the page
      temperature: not printed
    method: Product table, printed as 31 HRC max
    status: ground
    source: ati-product
    where: Plate, Sheet and Strip product tables (Hardness row)
  - benchmark: max_service_temp
    value: 316
    unit: °C
    scope: material
    bound: upper
    conditions:
      form: plate, sheet, strip, seamless tube and pipe (ASME Section VIII Division 1, UNS S31803)
      heat_treatment: not printed
      temperature: maximum 600 F (316 C)
    method: ASME Section VIII Division 1 approval limit for S31803, printed in the mechanical properties text
    status: ground
    source: ati-tds
    where: Mechanical Properties section, ASME approval paragraph
  - benchmark: max_service_temp
    value: 280
    unit: °C
    scope: material
    bound: upper
    conditions:
      form: pressure vessel applications (VdTÜV-Wb 418 and NGS 1606)
      heat_treatment: not printed
      temperature: 280 C (540 F) maximum for prolonged exposure
    method: Printed maximum for pressure vessel applications; prolonged exposure above 280 C changes the microstructure
    status: ground
    source: alleima-saf2205-pdf
    where: At high temperatures section
  - benchmark: pitting_resistance_equivalent
    value: 35.8
    unit: '-'
    scope: material
    conditions:
      form: typical ATI 2205 composition (minimum Cr 22.0, Mo 3.1, Ni 5.5, N 0.15)
      heat_treatment: not printed
      temperature: not applicable
    method: Printed typical PREN in the general properties text
    status: ground
    source: ati-tds
    where: General Properties, first page (typical PREN)
    note: Typical value, not a minimum (ATI says so)
  - benchmark: pitting_resistance_equivalent
    value: 35
    unit: '-'
    scope: material
    bound: lower
    conditions:
      form: nominal composition Cr 22, Mo 3.2, N 0.18 (SAF 2205)
      heat_treatment: not printed
      temperature: not applicable
    method: PRE table, SAF 2205 row, printed as greater than 35 (PRE = Cr + 3.3 Mo + 16 N)
    status: ground
    source: alleima-saf2205-pdf
    where: Pitting corrosion section, PRE table (SAF 2205 row)
    note: Printed as greater than 35 on nominal composition
  - benchmark: pitting_resistance_equivalent
    value: 35
    unit: '-'
    scope: material
    conditions:
      form: 2205 alloy (Rolled Alloys PREn table)
      heat_treatment: not printed
      temperature: not applicable
    method: Chloride Corrosion table, PREn printed as 35 for 2205 (PREn = Cr% + 3.3 x (Mo% + 0.5 x W%) + 16 x N%)
    status: ground
    source: rolled-2205
    where: Corrosion Resistance, Chloride Corrosion table (2205 row)
  - benchmark: pitting_resistance_equivalent
    value: 34
    unit: '-'
    scope: material
    conditions:
      form: Alloy 2205, composition basis not stated
      heat_treatment: solution annealed (Langley supply condition)
      temperature: not applicable
    method: Introduction text and Product Comparison table, PREN printed as 34
    status: ground
    source: langley-2205
    where: Introduction text and Product Comparison table (PREN row)
    note: Composition basis not stated; differs from 35.8 typical (ATI)
  - benchmark: critical_pitting_temperature
    value: 35
    unit: °C
    scope: material
    conditions:
      form: 2205 alloy (Rolled Alloys table)
      heat_treatment: not printed
      temperature: 35 C critical pitting temperature
      test: ASTM G48 in 6 percent ferric chloride
    method: Chloride Corrosion table, CPT printed as 95 F (35 C) for 2205, measured in 6% ferric chloride per ASTM G48
    status: ground
    source: rolled-2205
    where: Corrosion Resistance, Chloride Corrosion table (CPT column, 2205 row)
    note: ASTM G48 result; ATI quotes a different ASTM G 150 test
  - benchmark: fatigue_strength
    value: 430
    unit: MPa
    scope: material
    conditions:
      form: rotary bending specimen without notch
      heat_treatment: not printed
      temperature: 40 C
      environment: 3 percent NaCl, pH 7, 6000 rpm
      cycles: 2 x 10^7
    method: Corrosion fatigue table, printed as 430 MPa (62 ksi) for SAF 2205 without notch after 2 x 10^7 cycles
    status: ground
    source: alleima-saf2205-pdf
    where: Corrosion fatigue table (SAF 2205 row, specimen without notch)
  - benchmark: charpy_impact_energy
    value: 27
    unit: J
    scope: material
    bound: lower
    conditions:
      form: gas-shielded arc welded material (weld metal and heat-affected zone)
      heat_treatment: as welded
      temperature: '-50 C'
      test: Charpy V notch
    method: Welding impact text, minimum impact strength of 27 J (20 lb) at -50 C
    status: ground
    source: alleima-saf2205-pdf
    where: Impact strength section, welded material paragraph
corrosion:
  - environment: Seawater service, minimum PREN by alloy family
    headline: Rolled Alloys calls a minimum PREN of 40 typical for duplex stainless steels in seawater (45 for austenitic, 35 for ferritic), and says PREN is unsuitable for specification.
    effect: 'Rolled Alloys says that for seawater service austenitic stainless steels with a minimum PREn of 45, duplex stainless steels with a minimum PREn of 40, and ferritic stainless steels with a minimum PREn of 35 are typically considered suitable. It also says PREn is unsuitable for specification purposes and gives only a general ranking of alloys.'
    rating: unknown
    conditions:
      criterion: minimum PREn by family for seawater service (typically considered suitable)
      limit: PREn is a ranking, not a specification
    source: rolled-pren
    where: Comparing Alloys with PREn section
  - environment: Chloride stress corrosion cracking, chloride-bearing service
    headline: Ferrite phase gives resistance, substantially better than 300-series steels
    effect: ATI says the ferrite phase in ATI 2205 provides resistance to chloride stress corrosion cracking, making it substantially better than standard 300 series austenitic stainless steels. Duplex grades are often preferred over austenitics where chloride SCC is a problem. The datasheet shows this comparison as a graph, which was not read as numbers.
    rating: low
    conditions:
      environment: chloride-bearing service
      temperature: not stated in the text
    source: ati-tds
    where: Corrosion Properties, Chloride Stress Corrosion Cracking Resistance section
  - environment: Chloride stress corrosion cracking, CaCl2 and neutral chloride tests
    headline: TP304L and TP316L prone above 60 C; SAF 2205 much more resistant
    effect: Alleima says ASTM TP304L and TP316L are prone to stress corrosion cracking in chloride-bearing solutions above 60 C (140 F). Constant-load specimens loaded to proof strength (Figure 7) show 2205 with low susceptibility over a temperature and chloride range. In 40 percent CaCl2 at pH 6.5 and 100 C, aerated (Figure 8), 2205 resists SCC much better than TP304L and TP316L. Tests ran to failure or to a maximum of 500 h.
    rating: low
    conditions:
      environment: 40 percent CaCl2, pH 6.5, aerated; neutral chloride solutions with about 8 ppm oxygen (Figure 7)
      temperature: 100 C in the CaCl2 test; austenitic threshold above 60 C
    source: alleima-saf2205-pdf
    where: Stress corrosion cracking (SCC) section, Figures 7 and 8
  - environment: Chloride pitting and crevice corrosion
    headline: PREN 35 and critical pitting temperature 35 C (ASTM G48, 6 percent FeCl3)
    effect: Rolled Alloys gives PREn 35 for 2205 against 24 for 316/316L and 28 for 317/317L. Its critical pitting temperature is 95 F (35 C) against 50 F (10 C) for 316/316L, measured in 6 percent ferric chloride per ASTM G48. Alleima's PRE table gives 24 for TP316L and, for UNS S31803, chromium 21.0 to 23.0, molybdenum 2.50 to 3.50 and nitrogen 0.08 to 0.20 with PRE above 30. Alleima says 2205 resists crevice corrosion better than 316L.
    rating: low
    conditions:
      environment: 6 percent ferric chloride (ASTM G48)
      temperature: 35 C critical pitting temperature
    source: rolled-2205
    where: Corrosion Resistance, Chloride Corrosion table
  - environment: Sour service, hydrogen sulphide with chlorides
    headline: Sour service acceptable up to 232 C at limited H2S partial pressure
    effect: Alleima says solution annealed and cold-worked SAF 2205 is acceptable at up to 232 C (450 F) in sour service when the H2S partial pressure is at most 0.02 bar and hardness at most HRC 36 (NACE MR0175/ISO 15156). Solution annealed and rapidly cooled material is acceptable up to 232 C when the H2S partial pressure is at most 0.1 bar. NACE MR0103 accepts solution annealed and rapidly cooled material at HRC 28 maximum for sour refining. In NACE TM0177 solution A at room temperature, cracking needs about 1.1 times the 0.2 percent proof strength, and welded joints are slightly lower.
    rating: low
    conditions:
      temperature: up to 232 C (450 F)
      environment: H2S partial pressure 0.02 bar (cold-worked) or 0.1 bar (solution annealed)
      heat_treatment: solution annealed, or solution annealed and cold worked
    source: alleima-saf2205-pdf
    where: Stress corrosion cracking section, H2S paragraphs and Figure 9
  - environment: General corrosion in acids and most media
    headline: Better general corrosion resistance than 316L and 317L in most media
    effect: 'Alleima says SAF 2205 resists general corrosion better than TP316L and TP317L in most media, shown by isocorrosion diagrams for sulphuric and hydrochloric acid and by corrosion rates in boiling 50 percent acetic acid with formic acid mixtures (Figure 4). Where impurities raise corrosivity, it advises higher-alloyed grades: Alleima 2RK65, Sanicro 28 or SAF 2507.'
    rating: low
    conditions:
      temperature: boiling 50 percent acetic acid mixtures (Figure 4); stagnant tests (Figures 3 and 5)
      environment: sulphuric acid, hydrochloric acid, acetic and formic acid mixtures
    source: alleima-saf2205-pdf
    where: General corrosion section, Figures 3 to 5
  - environment: General corrosion in dilute and oxidizing acids; intergranular corrosion in welds
    headline: Resists dilute reducing acids and moderate to high oxidizing acids (ATI)
    effect: ATI says the alloy resists dilute reducing acids and moderate to high concentrations of oxidizing acids. It resists low concentrations of organic acids, but higher concentrations at elevated temperatures need caution. Welded samples resist intergranular corrosion in the 16 percent sulphuric acid copper sulphate test (ASTM A 262 Practice E).
    rating: low
    conditions:
      environment: dilute reducing acids; moderate to high oxidizing acids; welds tested in 16 percent sulphuric acid with copper sulphate
      temperature: elevated temperature for organic acids (no number printed)
    source: ati-tds
    where: Corrosion Properties, General Corrosion Resistance and Intergranular Corrosion sections
risks:
  hazards:
    - text: PubChem aggregated GHS notifications for elemental nickel include H317, H334, H351, H372 and H412, with signal word Danger in some notifications. These cover the element, not the 2205 alloy.
      ghs:
        - H317
        - H334
        - H351
        - H372
        - H412
      source: pubchem-nickel
      where: UN GHS Classification (PubChem record, CID 935)
    - text: PubChem notifications for elemental chromium include H317, H319, H334, H335, H341, H400 and H410. Signal words differ between notifications (Danger and Warning). The record is not a supplier classification.
      ghs:
        - H317
        - H319
        - H334
        - H335
        - H341
        - H400
        - H410
      source: pubchem-chromium
      where: UN GHS Classification (PubChem record, CID 23976)
    - text: PubChem notifications for elemental molybdenum include H315, H319, H335 and H361 (suspected of damaging fertility or the unborn child), with signal words Warning and Danger across notifications.
      ghs:
        - H315
        - H319
        - H335
        - H361
      source: pubchem-molybdenum
      where: UN GHS Classification (PubChem record, CID 23932)
  failure_risks:
    - mode: 885 F (475 C) embrittlement of the ferrite phase
      trigger: Extended exposure at 343 to 530 C (650 to 1000 F)
      consequence: Raises the ductile-to-brittle transition temperature. ATI says this range must be avoided in fabrication and service, and heat treatment above 590 C reverses the embrittlement.
      severity: high
      source: ati-tds
      where: Impact Properties and Effect of Elevated Temperature on Mechanical Properties sections
    - mode: Loss of impact strength after prolonged high-temperature exposure
      trigger: Prolonged exposure above 280 C (540 F)
      consequence: The microstructure changes and impact strength falls. For pressure vessels, 280 C is the maximum (VdTÜV-Wb 418 and NGS 1606).
      severity: moderate
      source: alleima-saf2205-pdf
      where: At high temperatures section
    - mode: Brittle weld metal from straight chromium filler or a fully ferritic weld
      trigger: Welding with straight chromium stainless steel filler metals, or a fully ferritic weld
      consequence: Raises the weld's susceptibility to brittle impact behaviour. Matching AWS E2209 fillers are commercially available.
      severity: moderate
      source: ati-tds
      where: Impact Properties and Welding sections
    - mode: Sulphide stress cracking in sour service
      trigger: H2S partial pressure above 0.02 bar with hardness above HRC 36 (cold-worked), above 0.1 bar (solution annealed), or temperature above 232 C
      consequence: Cracking risk rises, and welded joints are slightly less resistant than base metal
      severity: moderate
      source: alleima-saf2205-pdf
      where: Stress corrosion cracking section, H2S paragraphs
    - mode: Pitting and crevice attack in chloride service
      trigger: Chloride service above the 35 C critical pitting temperature (ASTM G48, 6 percent FeCl3)
      consequence: Local attack. The datasheets rank 2205 above 316L, but no service temperature limit for chloride pitting is printed in the fetched sources.
      severity: moderate
      source: rolled-2205
      where: Corrosion Resistance, Chloride Corrosion table
    - mode: Damage from stress relief and cold bending in chloride service
      trigger: Stress relief between 316 and 926 C, or heavy cold bending in chloride service without a full anneal
      consequence: Stress relief in this range adversely affects the properties. Heavily cold-bent sections should be fully annealed when SCC is possible.
      severity: moderate
      source: ati-tds
      where: Forming section (page 6)
  side_effects: []
  handling:
    - text: Solution anneal at 1020 to 1100 C and cool quickly in air or water (Alleima, ATI). Langley gives 1060 to 1120 C for at least one hour, followed by an immediate water quench.
      source: alleima-saf2205-pdf
      where: Heat treatment, Solution annealing
    - text: Weld with E2209 or ER2209 filler, without preheating, at heat input of 0.5 to 2.5 kJ/mm and interpass temperature below 150 C (Alleima).
      source: alleima-saf2205-pdf
      where: Welding section
    - text: Cold bending to 25 percent deformation needs no subsequent heat treatment, though heat treatment is advised where SCC risk rises (Alleima). Use a bend radius of at least twice the thickness (ATI).
      source: alleima-saf2205-pdf
      where: Bending section
    - text: Expansion into tubesheets needs higher initial force and should be done in one operation (Alleima).
      source: alleima-saf2205-pdf
      where: Expanding section
    - text: Machine at a lower cutting speed than 304 or 316, with a tougher insert grade, since built-up edges and chipping are expected (Alleima).
      source: alleima-saf2205-pdf
      where: Machining section
  mitigations:
    - text: A full anneal and rapid cooling removes 475 C embrittlement, and heat treatment above 590 C reverses it (ATI).
      source: ati-tds
      where: Effect of Elevated Temperature on Mechanical Properties
    - text: Where active corrosion is a risk, choose a higher-alloyed grade such as Alleima 2RK65 or Sanicro 28, or super-duplex SAF 2507 (Alleima).
      source: alleima-saf2205-pdf
      where: General corrosion section
    - text: Use matching AWS E2209 fillers so the weld keeps a phase balance close to the base metal (ATI).
      source: ati-tds
      where: Welding section
uses:
  - application: structures
    device: Chemical process vessels, piping and heat exchangers
    example: Rolled Alloys lists chemical process vessels, piping and heat exchangers, FGD scrubber systems, pulp mill digesters, bleach washers, chip presteaming vessels and food process equipment for 2205.
    source: rolled-2205
    where: Applications list
  - application: structures
    device: Oil and gas production tubing, flowlines and heat exchangers in sour service
    example: Alleima lists production tubing and flowlines for sour wells, refineries and chloride-contaminated process solutions, and heat exchangers that use chloride-bearing or brackish cooling water.
    source: alleima-saf2205-pdf
    where: Applications section
  - application: mechanisms
    device: Marine propellers, shafts, rudders, pumps and valves
    example: Langley lists marine propellers, shafts, rudders, shaft seals, pumps and valves, and oil and chemical tankers for Alloy 2205.
    source: langley-2205
    where: Applications list
supply:
  - subject: Nickel production by country (USGS 2026)
    abundance: World mine production about 3,900,000 t in 2025 (estimated, world total rounded). World reserves more than 140,000,000 t, of which Indonesia holds 62,000,000 t. Stainless and alloy steel plus nickel-containing alloys take more than 85 percent of US domestic consumption, and US net import reliance was 41 percent of apparent consumption in 2025 (estimated). Shares are computed from the printed tonnage divided by the printed world total.
    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, and 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)
    source: usgs-nickel-2026
    where: World Mine Production and Reserves; Domestic Production and Use; Recycling; Substitutes
  - subject: Chromium production by country (USGS 2026)
    abundance: World mine production 51,000 thousand t in 2025 (estimated, gross weight). World resources greater than 12 billion t of shipping-grade chromite, 95 percent in Kazakhstan and southern Africa. US net import reliance was 79 percent of apparent consumption in 2025 (estimated). Chromite imports for 2021 to 2024 came 96 percent from South Africa and 3 percent from Turkey. Shares are computed from the printed gross-weight tonnage.
    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; World Resources; Salient Statistics; Recycling; Substitutes
  - subject: Molybdenum production by country (USGS 2026)
    abundance: World mine production 260,000 t of molybdenum content in 2025 (estimated). China, Chile, the United States, Peru and Mexico account for 90 percent of world production. China imposed export controls on molybdenum powders in February 2025. The United States is a net exporter of molybdenum. Shares are computed from the printed tonnage divided by the printed world total.
    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 recycled as part of new and old steel and other scrap may be as much as 30 percent of apparent supply.
    substitutes:
      - Little substitution for molybdenum in steels; potential substitutes are boron, chromium, niobium and vanadium in alloy steels (USGS 2026)
    source: usgs-molybdenum-2026
    where: World Mine Production and Reserves; Recycling; Substitutes; Events, Trends, and Issues
media: []
documents:
  - title: ATI 2205 Technical Data Sheet, version 4 (2015)
    type: datasheet
    url: https://atimaterials.com/Products/Documents/datasheets/stainless-specialty-steel/duplex/ati_2205_tds_en_v4.pdf
    year: 2015
  - title: ATI 2205 duplex stainless steel product page (UNS S31803 and/or S32205)
    type: datasheet
    url: https://www.atimaterials.com/Products/ati-2205
    year: 2026
  - title: Alleima SAF 2205 tube and pipe, seamless datasheet (updated 2026-02-11)
    type: datasheet
    url: https://www.alleima.com/en/technical-center/material-datasheets/tube-and-pipe-seamless/saf-2205?show=pdf
    year: 2026
  - title: Rolled Alloys 2205 Duplex data sheet
    type: datasheet
    url: https://www.rolledalloys.com/wp-content/uploads/2022/07/2205_Duplex_Stainless_DataSheet_RolledAlloys.pdf
    year: 2026
  - title: Langley Alloys DS-Alloy 2205 data sheet (5/2017)
    type: datasheet
    url: https://www.langleyalloys.com/wp-content/uploads/2021/07/Datasheet-DS-Alloy-2205-rev2.pdf
    year: 2017
  - title: 'ICAST Alloys: ASTM A240 UNS S32205 summary'
    type: datasheet
    url: https://www.icastllp.com/material_db_pdf/ASTM%20A240%20UNS%20S32205.pdf
  - 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), UN GHS classification'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/935/JSON
  - title: 'PubChem: Chromium (CID 23976), UN GHS classification'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23976/JSON
  - title: 'PubChem: Molybdenum (CID 23932), UN GHS classification'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23932/JSON
gaps:
  - The 300 C embrittlement limit is not printed in any fetched source. Printed limits are 280 C for pressure vessels (Alleima), 316 C (600 F) under ASME Section VIII (ATI, Rolled Alloys), and an avoidance band of 343 to 530 C (ATI).
  - No cryogenic 2205 data (4 K or 20 K yield or tensile) were found. A NASA NTRS search returned no 2205 record.
  - No Outokumpu 2205 datasheet was reached. The search returned only a Prospector listing behind a sign-up, so no Outokumpu values are used.
  - The ATI TDS room-temperature mechanical table and the chloride SCC and critical pitting results are images in the PDF. Only printed text was used, so their numbers are not in this file.
  - The ATI product page prints carbon max 0.30 for plate, sheet and strip. The ASTM A240 sources print 0.030, so 0.030 is used.
  - Langley's composition table did not parse cleanly and its ksi conversions are wrong (450 N/mm2 printed as 91.4 ksi). Only Langley's metric physical values are used, and its composition is not used.
  - 'Physical values differ between sources and are kept side by side, not averaged: density (ATI 7.82, Alleima 7.8 g/cm3), modulus (Alleima 200 GPa at 20 C, Langley 190 kN/mm2), CTE (Alleima 13.0 for 30 to 100 C, Langley 11 for 20 to 300 C), specific heat (480 and 400 J/kg K), thermal conductivity (14 and 15 W/m K), resistivity (0.74 and 0.85 micro-ohm m).'
  - 'PREN depends on the composition basis: 35.8 typical (ATI), above 35 on nominal composition (Alleima), 35 (Rolled Alloys), 34 (Langley). None was calculated for this file.'
  - The MDPI Metals 2016 paper on 2205 atmospheric SCC after 475 C ageing refused the fetch (Access Denied), so it gives no test numbers here.
  - The chloride SCC and critical pitting results in the ATI and Alleima datasheets are graphs. Only their text claims are recorded.
  - The melting range is printed only in imperial units by Rolled Alloys (2525 to 2625 F), so it is kept as printed.
  - 'Hardness is not in the canonical property list, so the name hardness is used (ICAST in HB, ATI in HRC). PREN, critical pitting temperature and welded Charpy energy are also not canonical, so snake_case names are used: pitting_resistance_equivalent, critical_pitting_temperature and charpy_impact_energy.'
  - Critical-mineral lists (USGS, EU, BGS) were not read for nickel, chromium or molybdenum, so critical_lists are empty. The USGS 2026 nickel text names Executive Order 14285 only.
  - Hazards are PubChem records for elemental nickel, chromium and molybdenum. No safety data sheet for 2205 was read, so welding-fume hazards for this grade are not covered.
  - No NASA or ESA source naming 2205 in a spacecraft part was found, so the uses come from datasheets and distributors and the space link is not sourced.
  - The UPMET 2205 PDF link returned a page with no data, the Atlas Steels 2205 sheet returned empty text, and the ORNL embrittlement page returned only a landing page. None of these is used.
  - The Jacquet 2205 technical sheet repeats the ATI TDS text, so it is not counted as a separate source.
  - Supply shares are computed from printed tonnages divided by printed world totals. USGS does not print them as percentages.
sources:
  ati-tds:
    title: 'ATI 2205 Technical Data Sheet, version 4 (2015): Duplex Stainless Steel (UNS S31803 and S32205)'
    id: ati_2205_tds_en_v4
    url: https://atimaterials.com/Products/Documents/datasheets/stainless-specialty-steel/duplex/ati_2205_tds_en_v4.pdf
    kind: datasheet
    year: 2015
    license: cited, not reproduced
  ati-product:
    title: 'ATI: 2205 Duplex Stainless Steel, UNS S31803 and/or S32205 (plate, sheet and strip)'
    id: ati-2205
    url: https://www.atimaterials.com/Products/ati-2205
    kind: datasheet
    year: 2026
    license: cited, not reproduced
  alleima-saf2205-pdf:
    title: 'Alleima: SAF 2205 Tube and pipe, seamless datasheet (updated 2026-02-11)'
    id: SAF 2205 seamless tube and pipe
    url: https://www.alleima.com/en/technical-center/material-datasheets/tube-and-pipe-seamless/saf-2205?show=pdf
    kind: datasheet
    year: 2026
    license: cited, not reproduced
  rolled-pren:
    title: 'Rolled Alloys: PREN Calculator (comparing alloys by pitting resistance equivalent)'
    id: PREN Calculator
    url: https://www.rolledalloys.com/pren-calculator/
    kind: web
    year: 2026
    license: cited, not reproduced
  rolled-2205:
    title: 'Rolled Alloys: 2205 Duplex data sheet'
    id: 2205_Duplex_Stainless_DataSheet_RolledAlloys
    url: https://www.rolledalloys.com/wp-content/uploads/2022/07/2205_Duplex_Stainless_DataSheet_RolledAlloys.pdf
    kind: datasheet
    year: 2026
    license: cited, not reproduced
  langley-2205:
    title: 'Langley Alloys: DS-Alloy 2205 data sheet (5/2017)'
    id: DS-Alloy 2205
    url: https://www.langleyalloys.com/wp-content/uploads/2021/07/Datasheet-DS-Alloy-2205-rev2.pdf
    kind: datasheet
    year: 2017
    license: cited, not reproduced
  icast-s32205:
    title: 'ICAST Alloys: ASTM A240 UNS S32205 chemical composition and mechanical summary'
    id: ASTM A240 UNS S32205
    url: https://www.icastllp.com/material_db_pdf/ASTM%20A240%20UNS%20S32205.pdf
    kind: datasheet
    license: cited, not reproduced
  wiki-saf2205:
    title: 'Wikipedia: SAF 2205 (history and designations only)'
    id: SAF 2205
    url: https://en.wikipedia.org/wiki/SAF_2205
    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), UN 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), UN 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), UN 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: 37
  unreachable: 0
  caveats: 10
  note: 'Read by an AI assistant on 2026-10-24 from pages fetched in this run: ATI 2205 TDS version 4 and product page, Alleima SAF 2205 datasheet, Rolled Alloys 2205 data sheet, Langley Alloys DS-Alloy 2205, ICAST ASTM A240 UNS S32205 summary, Wikipedia SAF 2205 (history and designations only), USGS MCS 2026 nickel, chromium and molybdenum, and PubChem nickel, chromium and molybdenum. Not used: UPMET 2205 link (no data), Atlas Steels 2205 (empty text), ORNL landing page (no data), MDPI Metals 2016 (Access Denied). The ATI product page prints carbon max 0.30; the ASTM A240 sources print 0.030, so 0.030 is used. identity.designations is kept as requested; the site schema has no such field.'
story:
  why: Duplex 2205 is an austenite-ferrite steel with roughly twice the proof strength of conventional austenitic stainless steels, a typical PREN of 35.8 (ATI), and substantially better chloride stress corrosion cracking resistance than 300-series steels (ATI, Alleima). Its main limits are the 475 C embrittlement band of 343 to 530 C, which ATI says to avoid, and the 280 C maximum that Alleima gives for pressure vessels.
  recipe:
    line: Duplex 2205 is a nitrogen-enhanced austenite-ferrite steel with nearly equal parts of each phase in the annealed condition (ATI). Composition limits in wt percent for UNS S32205 under ASTM A240 are chromium 22.0 to 23.0, nickel 4.5 to 6.5, molybdenum 3.0 to 3.5, nitrogen 0.14 to 0.20, carbon 0.030 max, manganese 2.0 max, silicon 1.0 max, phosphorus 0.030 max, sulphur 0.020 max and iron as the balance (ICAST, Rolled Alloys). Wikipedia says UNS S31803 came first and UNS S32205 followed from later changes to it. Langley describes the route as VOD or AOD refining, optional ESR, a forging ratio of at least 4 to 1, then solution treatment at 1060 to 1120 C for at least one hour and a water quench.
    parts:
      - name: Iron
        symbol: Fe
        share_note: balance (the rest)
        role: Matrix of the alloy, with the austenite and ferrite phases.
      - name: Chromium
        symbol: Cr
        share_percent: 22
        share_high: 23
        role: Forms the passive film and gives most of the pitting resistance (PREN).
      - name: Nickel
        symbol: Ni
        share_percent: 4.5
        share_high: 6.5
        role: Stabilises the austenite; the ferrite carries less nickel than the austenite (ATI).
      - name: Molybdenum
        symbol: Mo
        share_percent: 3
        share_high: 3.5
        role: Raises pitting and crevice resistance and strength at elevated temperature.
      - name: Nitrogen
        symbol: 'N'
        share_percent: 0.14
        share_high: 0.2
        role: Raises pitting resistance and welded properties; ATI produces to a higher minimum than the ASTM range.
      - name: Carbon
        symbol: C
        share_percent: 0
        share_high: 0.03
        role: Kept low to limit chromium carbide precipitation (maximum limit).
      - name: Manganese
        symbol: Mn
        share_percent: 0
        share_high: 2
        role: Deoxidiser and austenite former in the melt (maximum limit).
      - name: Silicon
        symbol: Si
        share_percent: 0
        share_high: 1
        role: Deoxidiser in the melt (maximum limit).
      - name: Phosphorus
        symbol: P
        share_percent: 0
        share_high: 0.03
        role: Impurity held low (maximum limit).
      - name: Sulphur
        symbol: S
        share_percent: 0
        share_high: 0.02
        role: Impurity held low (maximum limit).
  risk_groups:
    - title: For people
      level: 0
      verdict: Element records, not alloy tests
      lead: PubChem lists hazards for elemental nickel, chromium and molybdenum. No 2205 safety data sheet was read.
      points:
        - label: Nickel
          line: PubChem lists H317, H334, H351, H372 and H412 for elemental nickel.
        - label: Chromium
          line: PubChem lists H317, H319, H334, H335, H341, H400 and H410 for elemental chromium.
        - label: Molybdenum
          line: PubChem lists H315, H319, H335 and H361 for elemental molybdenum.
    - title: In the environment
      level: 1
      verdict: Chloride and sour service are the watch points
      lead: Pitting, crevice attack and sour cracking are the main routes in service.
      points:
        - label: Chloride
          line: Critical pitting temperature 35 C in 6 percent FeCl3 (ASTM G48), with PREN 35 or above.
        - label: Sour service
          line: Alleima limits sour service to 232 C at 0.02 to 0.1 bar H2S, depending on heat treatment.
    - title: Heat history
      level: 2
      verdict: Heat history sets the risk
      lead: The 475 C embrittlement band and the stress relief range both come from heat history.
      points:
        - label: Band
          line: ATI says extended exposure at 343 to 530 C must be avoided in fabrication and service.
        - label: Fix
          line: A full anneal and rapid cooling removes the embrittlement, and heat treatment above 590 C reverses it (ATI).
  uses:
    - where: Chemical process vessels, piping and heat exchangers
      line: Rolled Alloys lists these, plus FGD scrubber systems, pulp mill digesters and food process equipment.
    - where: Oil and gas production tubing, flowlines and sour-service heat exchangers
      line: Alleima lists production tubing and flowlines for sour wells, refineries and chloride-contaminated process solutions.
    - where: Marine propellers, shafts, rudders and pumps
      line: Langley lists these for Alloy 2205, along with oil and chemical tankers.
  can_do:
    - label: Strength
      benchmark: yield_strength
      line: Minimum 0.2 percent yield is 450 MPa for ASTM A240 plate and sheet (ATI, ICAST). Alleima gives at least 485 MPa for tube and pipe up to 20 mm wall.
    - label: Tensile
      benchmark: ultimate_tensile_strength
      line: Minimum tensile strength is 655 MPa for ASTM A240 (ATI, ICAST). Alleima tube and pipe reaches 680 to 880 MPa.
    - label: Stiffness
      benchmark: elastic_modulus
      line: Elastic modulus is 200 GPa at 20 C (Alleima), and Langley gives 190 kN/mm2.
    - label: Density
      benchmark: density
      line: Density is 7.82 g/cm3 (ATI) and 7.8 g/cm3 (Alleima).
    - label: Chloride pitting
      benchmark: pitting_resistance_equivalent
      line: PREN is 35.8 typical (ATI). Alleima prints greater than 35 on nominal composition, against 24 for TP316L.
    - label: Sour service
      line: Acceptable in sour service up to 232 C at limited H2S partial pressure (Alleima, NACE MR0175/ISO 15156).
  compare: 'Against 316L, 2205 has the higher PREN: about 35 on Alleima''s nominal composition, against 24 for TP316L in the same PRE table. Its proof strength is roughly twice that of conventional austenitic steels (ATI, Alleima). Alleima says TP304L and TP316L are prone to chloride stress corrosion cracking above 60 C, while 2205 resists it much better. The trade-off is the 475 C embrittlement band from 343 to 530 C that ATI says to avoid.'
  compare_rows:
    - label: Tensile strength
      benchmark: ultimate_tensile_strength
      scope: material
    - label: Density
      benchmark: density
      scope: material
    - label: Yield strength
      benchmark: yield_strength
      scope: material
  handling:
    - Solution anneal at 1020 to 1100 C and cool quickly in air or water (Alleima, ATI).
    - Weld with E2209 or ER2209 filler, without preheating, at a heat input of 0.5 to 2.5 kJ/mm (Alleima).
    - Avoid stress relief between 316 and 926 C, which harms the properties (ATI).
    - Expand tubes in one operation with higher initial force (Alleima).
  good_for:
    - Chloride service above 60 C, where TP304L and TP316L are prone to stress corrosion cracking (Alleima).
    - 'Pressure parts and piping: 280 C maximum for pressure vessels (Alleima), 316 C under ASME (ATI).'
    - Heavy-load structures and tubing that need roughly twice the strength of austenitic steels (ATI, Alleima).
  watch_out:
    - The 475 C embrittlement band from 343 to 530 C, which must be avoided in fabrication and service (ATI).
    - Sour service is limited to 232 C, and to 0.02 or 0.1 bar H2S partial pressure depending on heat treatment (Alleima).
    - Welds made with straight chromium filler metal, or a fully ferritic weld, lose impact toughness (ATI).
  verdict: Duplex 2205 is a strong, chloride-resistant option, with a typical PREN of 35.8 (ATI) and a minimum yield of 450 MPa for plate (ATI, ICAST). Use solution annealed material, avoid 343 to 530 C in fabrication and service, and respect the 280 C pressure-vessel maximum (Alleima). No source in this file ties it to a space part, so the space link is open.