spore: profile
id: monel-400
spore_version: 0.2
family: nickel-alloys
name: Monel 400
abbreviation: Alloy 400 (UNS N04400)
role: corrosion-resistant solid-solution nickel-copper alloy
category: metals
type: nickel-superalloys
summary: |
  Monel 400 (UNS N04400, W.Nr. 2.4360 and 2.4361) is a single-phase nickel-copper solid-solution alloy with at least 63.0 percent nickel plus cobalt and 28.0 to 34.0 percent copper. Special Metals says it can be hardened only by cold working, and that it combines high strength and toughness with excellent resistance to many corrosive environments, especially seawater and hydrofluoric acid. Annealed material is the softest condition: Special Metals gives 75 to 90 ksi tensile for annealed rod and bar, and ATI gives 75,000 psi typical for annealed plate, sheet and strip.
best_for: Seawater, hydrofluoric-acid and reducing-acid service, and marine valves, pump shafts and fasteners, where corrosion resistance matters more than high strength
weakest_at: Stagnant seawater (crevice and pitting corrosion), caustic at high temperature and stress (stress-corrosion cracking), and low strength in the annealed condition
identity:
  formula: 'Nickel-copper solid-solution alloy: 63.0 min nickel plus cobalt, 28.0 to 34.0 copper, 2.5 max iron, 2.0 max manganese, 0.5 max silicon, 0.3 max carbon, 0.024 max sulfur (wt%)'
  source: sm-monel400
  where: Table 1, Limiting Chemical Composition (Special Metals); UNS N04400 and W.Nr. 2.4360 and 2.4361 from the opening paragraph; the plate, sheet and strip composition on the ATI product page agrees
  designations:
    - system: UNS
      code: N04400
      source: sm-monel400
      where: Opening paragraph, UNS N04400 with W.Nr. 2.4360 and 2.4361; Available Products and Specifications
    - system: EN
      code: '2.4360'
      source: sm-monel400
      where: Available Products and Specifications, Werkstoff Nr. 2.4360 and 2.4361
    - system: EN
      code: '2.4361'
      note: printed with 2.4360
      source: sm-monel400
      where: Available Products and Specifications, the second number printed for this alloy
    - system: EN name
      code: NiCu30Fe
      source: wiki-monel
      where: Reference list, citation title Monel 400 (NiCu30Fe, 2.4360, N04400, NA13)
    - system: ASTM
      code: B127
      note: plate, sheet and strip
      source: sm-monel400
      where: Available Products and Specifications, Plate, Sheet, and Strip list
    - system: ASTM
      code: B163
      note: condenser and heat exchanger tube
      source: sm-monel400
      where: Available Products and Specifications, Pipe and Tube list
    - system: ASTM
      code: B164
      note: rod, bar and wire
      source: sm-monel400
      where: Available Products and Specifications, Bar, Rod, Wire, and Forgings list
    - system: ASTM
      code: B165
      note: seamless pipe and tube
      source: sm-monel400
      where: Available Products and Specifications, Pipe and Tube list
    - system: ASTM
      code: B564
      note: forgings
      source: sm-monel400
      where: Available Products and Specifications, Bar, Rod, Wire, and Forgings list
    - system: ASME
      code: SB 127
      note: plate, sheet and strip
      source: sm-monel400
      where: Available Products and Specifications, Plate, Sheet, and Strip list
    - system: ASME
      code: SB 164
      note: rod, bar and wire
      source: sm-monel400
      where: Available Products and Specifications, Bar, Rod, Wire, and Forgings list
    - system: ASME
      code: SB 165
      note: seamless pipe and tube
      source: sm-monel400
      where: Available Products and Specifications, Pipe and Tube list
    - system: AMS
      code: '4544'
      note: sheet, strip and plate
      source: sm-monel400
      where: Available Products and Specifications, Plate, Sheet, and Strip list
    - system: AMS
      code: '4574'
      note: seamless tubing
      source: sm-monel400
      where: Available Products and Specifications, Pipe and Tube list
    - system: AMS
      code: '4675'
      note: bars and forgings
      source: sm-monel400
      where: Available Products and Specifications, Bar, Rod, Wire, and Forgings list
    - system: AMS
      code: '4730'
      note: wire
      source: sm-monel400
      where: Available Products and Specifications, Bar, Rod, Wire, and Forgings list
    - system: AMS
      code: '4731'
      note: wire and ribbon
      source: sm-monel400
      where: Available Products and Specifications, Bar, Rod, Wire, and Forgings list
    - system: Federal
      code: QQ-N-281
      note: plate, sheet, strip, bar, rod, wire and forgings
      source: sm-monel400
      where: Available Products and Specifications, QQ-N-281 entries
    - system: DIN
      code: '17750'
      note: plate, strip and sheet
      source: sm-monel400
      where: Available Products and Specifications, Plate, Sheet, and Strip list
    - system: DIN
      code: '17751'
      note: pipe and tube
      source: sm-monel400
      where: Available Products and Specifications, Pipe and Tube list
    - system: DIN
      code: '17752'
      note: rod and bar
      source: sm-monel400
      where: Available Products and Specifications, Bar, Rod, Wire, and Forgings list
    - system: DIN
      code: '17753'
      note: wire
      source: sm-monel400
      where: Available Products and Specifications, Bar, Rod, Wire, and Forgings list
    - system: DIN
      code: '17754'
      note: forgings
      source: sm-monel400
      where: Available Products and Specifications, Bar, Rod, Wire, and Forgings list
    - system: BS
      code: 3072 NA13
      note: sheet and plate
      source: sm-monel400
      where: Available Products and Specifications, Plate, Sheet, and Strip list
    - system: BS
      code: 3073 NA13
      note: strip
      source: sm-monel400
      where: Available Products and Specifications, Plate, Sheet, and Strip list
    - system: BS
      code: 3074 NA13
      note: tube
      source: sm-monel400
      where: Available Products and Specifications, Pipe and Tube list
    - system: BS
      code: 3075 NA13
      note: wire
      source: sm-monel400
      where: Available Products and Specifications, Bar, Rod, Wire, and Forgings list
    - system: BS
      code: 3076 NA13
      note: bar
      source: sm-monel400
      where: Available Products and Specifications, Bar, Rod, Wire, and Forgings list
    - system: Trade name
      code: MONEL alloy 400
      source: sm-monel400
      where: Title and Table 1 heading
    - system: Trade name
      code: Monel 400
      source: wiki-monel
      where: Alloy table, Monel 400 row
    - system: Trade name
      code: Alloy 400
      source: sm-monel400
      where: Introduction, Alloy 400 is widely used in many fields
    - system: Trade name
      code: ATI 400
      source: ati-tds
      where: Title page, ATI 400 alloy (UNS N04400)
tags:
  environments: []
  stresses: []
  applications:
    - propulsion-and-tanks
    - structures
    - thermal-control
    - mechanisms
properties:
  - benchmark: density
    value: 8.8
    unit: g/cm3
    scope: material
    conditions:
      basis: Table 2 physical constant; no test temperature or condition printed
    method: Table 2, Physical Constants, Density g/cm3 row, printed as 8.80; the lb/in3 row prints 0.318
    status: ground
    source: sm-monel400
    where: Table 2, Density g/cm3 row
  - benchmark: density
    value: 8.83
    unit: g/cm3
    scope: material
    conditions:
      basis: typical value on the ATI data sheet; no temperature or condition stated
    method: Density section, printed as 0.319 lb/in3 and 8.83 g/cm3; the specific gravity is also printed as 8.83
    status: ground
    source: ati-tds
    where: Physical Properties, Density section
  - benchmark: melting_point
    value: 1300
    value_high: 1350
    bound: range
    unit: °C
    scope: material
    conditions:
      basis: melting range as printed in Table 2 (2370 to 2460 F)
    method: Table 2, Melting Range, °C row, printed as 1300-1350; the F row prints 2370-2460
    status: ground
    source: sm-monel400
    where: Table 2, Melting Range, °C row
  - benchmark: curie_temperature
    value: 21
    value_high: 49
    bound: range
    unit: °C
    scope: material
    conditions:
      basis: Curie range as printed in Table 2 (70 to 120 F); some heats are magnetic at room temperature and others are not
    method: Table 2, Curie Temperature, °C row, printed as 21-49
    status: ground
    source: sm-monel400
    where: Table 2, Curie Temperature, °C row
  - benchmark: elastic_modulus
    value: 26
    unit: 10^3 ksi
    scope: material
    conditions:
      basis: tension modulus; no test temperature printed (Figure 1 gives the temperature effect and was not read)
    method: Table 2, Modulus of Elasticity, Tension row, printed as 26.0 (10^3 ksi); the compression row also prints 26.0
    status: ground
    source: sm-monel400
    where: Table 2, Modulus of Elasticity, Tension row
  - benchmark: elastic_modulus
    value: 180
    unit: GPa
    scope: material
    conditions:
      condition: annealed
      product: plate, sheet and strip
      temperature: room temperature
      basis: typical value on the ATI data sheet
    method: Mechanical Properties, Elastic Modulus column, annealed plate, sheet and strip row, printed as 26x10^6 psi (180 GPa)
    status: ground
    source: ati-tds
    where: Mechanical Properties, Properties Applicable to Plate, Sheet and Strip, Elastic Modulus column
  - benchmark: poissons_ratio
    value: 0.32
    unit: '-'
    scope: material
    conditions:
      basis: Table 2, Poisson's ratio row; no test temperature printed
    method: Table 2, Poisson's Ratio row, printed as 0.32
    status: ground
    source: sm-monel400
    where: Table 2, Poisson's Ratio row
  - benchmark: thermal_conductivity
    value: 22
    unit: W/m°C
    scope: material
    conditions:
      temperature: 70 F (21 C)
      basis: Table 3 row 70 F (21 C); footnote a says the values also apply to R-405, the free-machining version of this alloy
    method: Table 3, Thermal Conductivity W/m°C column, row 70 F (21 C), printed as 22.0; the Btu-in/h/ft2/F column prints 151 for the same row
    status: ground
    source: sm-monel400
    where: Table 3, Thermal Properties, row 70 F (21 C)
  - benchmark: specific_heat
    value: 427
    unit: J/kg°C
    scope: material
    conditions:
      temperature: 70 F (21 C)
      basis: Table 3 row 70 F (21 C); footnote a also applies to R-405
    method: Table 3, Specific Heat J/kg°C column, row 70 F (21 C), printed as 427; the Btu/lb/F column prints 0.102
    status: ground
    source: sm-monel400
    where: Table 3, Thermal Properties, row 70 F (21 C)
  - benchmark: electrical_resistivity
    value: 0.511
    unit: µΩ·m
    scope: material
    conditions:
      temperature: 70 F (21 C)
      condition: annealed material (footnote c)
      basis: Table 3 row 70 F (21 C)
    method: Table 3, Electrical Resistivity µΩ·m column, row 70 F (21 C), printed as 0.511
    status: ground
    source: sm-monel400
    where: Table 3, Thermal Properties, row 70 F (21 C)
  - benchmark: cte
    value: 14.2
    unit: µm/m°C
    scope: material
    conditions:
      condition: annealed material (footnote b)
      temperature: 70 F (21 C) to 200 F (100 C)
      basis: mean linear expansion from 70 F to the row temperature, as printed in Table 3
    method: Table 3, Mean Linear Expansion µm/m°C column, row 200 F (100 C), printed as 14.2; the in/in/F column prints 7.7 x 10^-6
    status: ground
    source: sm-monel400
    where: Table 3, Mean Linear Expansion, row 200 F (100 C)
  - benchmark: specific_heat
    value: 430
    unit: J/kg·K
    scope: material
    conditions:
      temperature: room temperature
      basis: room-temperature value printed on the ATI data sheet; condition not stated
    method: Physical Properties, Specific Heat, room temperature values, printed as 430 Joules/kg K
    status: ground
    source: ati-tds
    where: Physical Properties, Specific Heat
  - benchmark: electrical_resistivity
    value: 51
    unit: µΩ-cm
    scope: material
    conditions:
      basis: value printed on the ATI data sheet with no temperature or condition stated
    method: Physical Properties, Electrical Resistivity, printed as 51.0 Microhm-cm
    status: ground
    source: ati-tds
    where: Physical Properties, Electrical Resistivity
  - benchmark: cte
    value: 13.9
    unit: 10^-6/°C
    scope: material
    conditions:
      temperature: 70 F (21 C) to 200 F (93 C)
      basis: mean linear expansion, typical value on the ATI data sheet
    method: Linear Coefficient of Thermal Expansion table, row 200 F (93 C), 10^-6/C column, printed as 13.9; the 10^-6/F column prints 7.7
    status: ground
    source: ati-tds
    where: Linear Coefficient of Thermal Expansion table, row 200 F (93 C)
  - benchmark: ultimate_tensile_strength
    value: 75
    value_high: 90
    bound: range
    unit: ksi
    scope: material
    conditions:
      condition: annealed
      product: rod and bar
      temperature: room temperature
      basis: composite range for various product sizes, not for specification (footnote a)
    method: Table 4, Rod and Bar, Annealed row, tensile strength column, printed as 75-90 ksi (517-620 MPa)
    status: ground
    source: sm-monel400
    where: Table 4, Rod and Bar, Annealed row, Tensile Strength
  - benchmark: yield_strength
    value: 25
    value_high: 50
    bound: range
    unit: ksi
    scope: material
    conditions:
      condition: annealed
      product: rod and bar
      temperature: room temperature, 0.2 percent offset
      basis: composite range for various product sizes, not for specification (footnote a)
    method: Table 4, Rod and Bar, Annealed row, yield strength (0.2% offset) column, printed as 25-50 ksi (172-345 MPa)
    status: ground
    source: sm-monel400
    where: Table 4, Rod and Bar, Annealed row, Yield Strength
  - benchmark: elongation
    value: 35
    value_high: 60
    bound: range
    unit: '%'
    scope: material
    conditions:
      condition: annealed
      product: rod and bar
      temperature: room temperature
    method: Table 4 prints 60-35 percent for the annealed row; recorded here low to high
    status: ground
    source: sm-monel400
    where: Table 4, Rod and Bar, Annealed row, Elongation
  - benchmark: ultimate_tensile_strength
    value: 70
    value_high: 85
    bound: range
    unit: ksi
    scope: material
    conditions:
      condition: hot-rolled, annealed
      product: plate
      temperature: room temperature
      basis: composite range for various product sizes, not for specification (footnote a)
    method: Table 4, Plate, Hot-Rolled Annealed row, tensile strength column, printed as 70-85 ksi (482-586 MPa)
    status: ground
    source: sm-monel400
    where: Table 4, Plate, Hot-Rolled Annealed row, Tensile Strength
  - benchmark: yield_strength
    value: 28
    value_high: 50
    bound: range
    unit: ksi
    scope: material
    conditions:
      condition: hot-rolled, annealed
      product: plate
      temperature: room temperature, 0.2 percent offset
      basis: composite range for various product sizes, not for specification (footnote a)
    method: Table 4, Plate, Hot-Rolled Annealed row, yield strength column, printed as 28-50 ksi (193-345 MPa)
    status: ground
    source: sm-monel400
    where: Table 4, Plate, Hot-Rolled Annealed row, Yield Strength
  - benchmark: ultimate_tensile_strength
    value: 70
    value_high: 85
    bound: range
    unit: ksi
    scope: material
    conditions:
      condition: annealed
      product: plate (ASTM B127, ASME SB-127, AMS 4544)
      temperature: room temperature
      basis: minimum and maximum printed on the ATI product page
    method: ATI product page, plate table, annealed, printed as 70 min - 85 max ksi (485 min - 585 max MPa)
    status: ground
    source: ati-page
    where: ATI product page, Plate table, annealed, Tensile Strength
  - benchmark: yield_strength
    value: 28
    bound: lower
    unit: ksi
    scope: material
    conditions:
      condition: annealed
      product: plate (ASTM B127, ASME SB-127, AMS 4544)
      temperature: room temperature, 0.2 percent offset
      basis: minimum printed on the ATI product page
    method: ATI product page, plate table, annealed, printed as 28 min ksi (195 min MPa)
    status: ground
    source: ati-page
    where: ATI product page, Plate table, annealed, Yield Strength
  - benchmark: elongation
    value: 35
    bound: lower
    unit: '%'
    scope: material
    conditions:
      condition: annealed
      product: plate (ASTM B127, ASME SB-127, AMS 4544)
      temperature: room temperature
      basis: minimum printed on the ATI product page
    method: ATI product page, plate table, annealed, printed as 35% min
    status: ground
    source: ati-page
    where: ATI product page, Plate table, annealed, Elongation
  - benchmark: ultimate_tensile_strength
    value: 75000
    unit: psi
    scope: material
    conditions:
      condition: annealed
      product: plate, sheet and strip
      temperature: room temperature
      basis: typical value on the ATI data sheet
    method: Properties Applicable to Plate, Sheet and Strip, annealed row, ultimate tensile strength column, printed as 75,000 psi (520 MPa)
    status: ground
    source: ati-tds
    where: Mechanical Properties, Properties Applicable to Plate, Sheet and Strip, annealed row
  - benchmark: yield_strength
    value: 35000
    unit: psi
    scope: material
    conditions:
      condition: annealed
      product: plate, sheet and strip
      temperature: room temperature, 0.2 percent offset
      basis: typical value on the ATI data sheet
    method: Properties Applicable to Plate, Sheet and Strip, annealed row, yield strength column, printed as 35,000 psi (240 MPa)
    status: ground
    source: ati-tds
    where: Mechanical Properties, Properties Applicable to Plate, Sheet and Strip, annealed row
  - benchmark: elongation
    value: 45
    unit: '%'
    scope: material
    conditions:
      condition: annealed
      product: plate, sheet and strip
      temperature: room temperature
      basis: typical value in 2 in (51 mm) on the ATI data sheet
    method: Properties Applicable to Plate, Sheet and Strip, annealed row, elongation column, printed as 45 percent in 2 in (51 mm)
    status: ground
    source: ati-tds
    where: Mechanical Properties, Properties Applicable to Plate, Sheet and Strip, annealed row
  - benchmark: yield_strength
    value: 21000
    unit: psi
    scope: material
    conditions:
      condition: annealed
      temperature: 1000 F (538 C)
      basis: short-time test, 0.2 percent offset yield strength, typical value on the ATI data sheet
    method: Short Time Elevated Temperature Properties table, row 1000 F (538 C), printed as 21,000 psi (145 MPa)
    status: ground
    source: ati-tds
    where: Short Time Elevated Temperature Properties table, row 1000 F (538 C), yield strength column
  - benchmark: ultimate_tensile_strength
    value: 53000
    unit: psi
    scope: material
    conditions:
      condition: annealed
      temperature: 1000 F (538 C)
      basis: short-time test, typical value on the ATI data sheet
    method: Short Time Elevated Temperature Properties table, row 1000 F (538 C), printed as 53,000 psi (370 MPa)
    status: ground
    source: ati-tds
    where: Short Time Elevated Temperature Properties table, row 1000 F (538 C), ultimate tensile strength column
  - benchmark: electrical_conductivity
    value: 34
    unit: '% IACS'
    scope: material
    conditions:
      basis: approximate value in the Properties section; no temperature or condition printed
    method: Properties section, first paragraph on Monel alloy 400, printed as approximately 34% IACS
    status: ground
    source: wiki-monel
    where: Properties section, Monel alloy 400 paragraph
corrosion:
  - environment: Flowing seawater
    headline: Very low corrosion rates in flowing seawater (Special Metals); Wikipedia says it resists rapidly flowing seawater.
    effect: Special Metals says alloy 400 products exhibit very low corrosion rates in flowing seawater. No corrosion rate or exposure time is printed.
    rating: low
    conditions:
      condition: flowing seawater
      basis: qualitative statement, no corrosion rate or exposure time printed
    source: sm-monel400
    where: Corrosion Resistance section, first paragraph
  - environment: Stagnant seawater
    headline: Crevice and pitting corrosion in stagnant seawater (Special Metals).
    effect: Special Metals says stagnant conditions have been shown to induce crevice and pitting corrosion. No test result is printed.
    rating: moderate
    conditions:
      condition: stagnant seawater
      basis: qualitative statement, no test result printed
    source: sm-monel400
    where: Corrosion Resistance section, first paragraph
  - environment: Hydrofluoric acid, all concentrations up to the boiling point
    headline: Exceptional resistance to hydrofluoric acid in all concentrations up to the boiling point (Special Metals).
    effect: Special Metals says alloy 400 offers exceptional resistance to hydrofluoric acid in all concentrations up to the boiling point, and that it is perhaps the most resistant of all commonly used engineering alloys. No corrosion rate is printed.
    rating: low
    conditions:
      temperature: up to the boiling point
      basis: qualitative statement, no corrosion rate printed
    source: sm-monel400
    where: Corrosion Resistance section, hydrofluoric acid paragraph
  - environment: Range of media, including seawater, hydrofluoric acid, sulfuric acid and alkalies
    headline: ESPI Metals lists seawater, hydrofluoric acid, sulfuric acid and alkalies among the media in which Alloy 400 resists corrosion.
    effect: ESPI Metals describes Alloy 400 as having high strength and excellent corrosion resistance in a range of media, including seawater, hydrofluoric acid, sulfuric acid, and alkalies. This is a supplier summary, so it supports the Special Metals statements and gives no numbers.
    rating: low
    conditions:
      basis: qualitative supplier summary, no numbers
    source: espi-alloy400
    where: Alloy 400 entry, technical data page
  - environment: Stress-corrosion cracking in fresh and industrial waters
    headline: Resistant to stress-corrosion cracking and pitting in most fresh and industrial waters (Special Metals).
    effect: Special Metals says alloy 400 is also resistant to stress corrosion cracking and pitting in most fresh and industrial waters, and it recommends stress relief as a precaution against stress-corrosion cracking in certain environments.
    rating: low
    conditions:
      basis: qualitative statement; no test stress or medium printed
    source: sm-monel400
    where: Corrosion Resistance section, first paragraph; Working Instructions, Thermal Treatments
  - environment: Chloride stress-corrosion cracking
    headline: Exceptionally resistant to chloride stress-corrosion cracking (ATI).
    effect: ATI says the alloy is exceptionally resistant to chloride stress corrosion cracking. No test stress, medium or time is printed.
    rating: low
    conditions:
      basis: qualitative statement; no test stress or medium printed
    source: ati-tds
    where: Corrosion Resistance section, reducing acids paragraph
  - environment: Caustic at high temperature and high stress
    headline: Caustic stress-corrosion cracking can occur at high temperature, high stress and high caustic concentration (ATI).
    effect: ATI says the alloy is a consideration for cooler alkaline caustic conditions, but high temperature, high stress and high concentrations of caustic have produced caustic stress corrosion cracking in the material.
    rating: moderate
    conditions:
      condition: high temperature, high stress and high caustic concentration
      basis: qualitative statement; no temperatures or concentrations printed
    source: ati-tds
    where: Corrosion Resistance section, alkaline solutions paragraph
  - environment: Sulfur-bearing gases and molten sulfur
    headline: Attacked by sulfur-bearing gases above about 700 F (371 C); molten sulfur attacks it above about 500 F (260 C) (ATI).
    effect: ATI says the alloy is attacked in sulfur-bearing gases above about 700 F (371 C), and that molten sulfur attacks the alloy at temperatures over about 500 F (260 C).
    rating: moderate
    conditions:
      temperature: above about 700 F (371 C) in sulfur-bearing gases; over about 500 F (260 C) for molten sulfur
      basis: printed temperatures, no exposure time
    source: ati-tds
    where: Corrosion Resistance section, sulfur paragraph
  - environment: Sulfuric and hydrochloric acids under reducing conditions
    headline: Resists many forms of sulfuric and hydrochloric acid under reducing conditions (Special Metals; ATI).
    effect: Special Metals says alloy 400 is resistant to many forms of sulfuric and hydrochloric acids under reducing conditions. ATI says it is used in reducing acids such as sulfuric and hydrochloric, especially in the absence of aeration and oxidising species.
    rating: low
    conditions:
      basis: qualitative statements; no concentrations or temperatures printed
    source: sm-monel400
    where: Corrosion Resistance section, last paragraph
  - environment: Highly oxidising acids, nitric and nitrous
    headline: Not useful in highly oxidising acids such as nitric or nitrous acid (ATI).
    effect: ATI says the alloy is not useful in highly oxidising acids such as nitric or nitrous acids, and points to high-chromium stainless steels for those environments.
    rating: severe
    conditions:
      basis: qualitative statement
    source: ati-tds
    where: Corrosion Resistance section, first paragraph
  - environment: Galvanic contact with steel in salt water
    headline: Galvanic attack on steel in salt water, so Monel must be insulated from steel in shipbuilding (Wikipedia).
    effect: Wikipedia says electrolytic action in salt water means Monel must be carefully insulated from other metals such as steel, and it records a yacht whose steel skeleton deteriorated through electrolytic interaction with Monel.
    rating: moderate
    conditions:
      condition: direct contact with steel in salt water
      basis: qualitative account, no rate printed
    source: wiki-monel
    where: Marine applications section
  - environment: Sour oil and gas service (NACE MR-01-75)
    headline: Listed in NACE MR-01-75 for oil and gas service; no sour-service test result was read.
    effect: Special Metals says the alloy is listed in NACE MR-01-75 for oil and gas service. No sour-service test data were read in this run.
    rating: unknown
    conditions:
      standard: NACE MR-01-75 (listed)
    source: sm-monel400
    where: Available Products and Specifications
  - environment: Creep and long-term high temperature
    headline: ATI says creep resistance should be considered above about 650 F (343 C).
    effect: ATI says creep resistance should be a consideration above about 650 F (343 C). No creep or rupture data were read.
    rating: unknown
    conditions:
      temperature: above about 650 F (343 C)
      basis: qualitative statement; no creep data printed
    source: ati-tds
    where: Short Time Elevated Temperature Properties, introductory paragraph
risks:
  hazards:
    - text: PubChem aggregated GHS for nickel metal (CID 935) from 4778 company reports lists H317 in 99.9 percent of reports that give a code, H351 in 72.9 percent, H372 in 99.7 percent, H350 in 22.5 percent, H360F in 18 percent, H341 in 13.5 percent, H334 in 10.3 percent and H412 in 47.2 percent. Nickel is about 63 percent of this alloy, so the record describes the metal, not the alloy.
      ghs:
        - H317
        - H351
        - H372
        - H350
        - H360F
        - H341
        - H334
        - H412
      source: pubchem-nickel
      where: Safety and Hazards, GHS Classification (PubChem PUG View JSON, aggregated ECHA C&L notifications)
    - text: PubChem aggregated GHS for copper metal (CID 23978) from 3463 company reports lists H400 in 43.1 percent of reports that give a code, H410 in 18.8 percent, H411 in 22.5 percent and H302 in 21.7 percent. Copper is 28.0 to 34.0 percent of this alloy, so the record describes the metal, not the alloy.
      ghs:
        - H400
        - H410
        - H411
        - H302
      source: pubchem-copper
      where: Safety and Hazards, GHS Classification (PubChem PUG View JSON, aggregated ECHA C&L notifications)
  failure_risks:
    - mode: Crevice and pitting corrosion in stagnant seawater
      trigger: Stagnant seawater, rather than flowing seawater
      consequence: Special Metals says stagnant conditions have been shown to induce crevice and pitting corrosion.
      severity: moderate
      source: sm-monel400
      where: Corrosion Resistance section, first paragraph
    - mode: Caustic stress-corrosion cracking
      trigger: High temperature, high stress and high concentrations of caustic
      consequence: ATI says these conditions have produced caustic stress corrosion cracking in the material.
      severity: high
      source: ati-tds
      where: Corrosion Resistance section, alkaline solutions paragraph
    - mode: Attack by sulfur-bearing gases and molten sulfur
      trigger: Sulfur-bearing gases above about 700 F (371 C); molten sulfur above about 500 F (260 C)
      consequence: ATI says the alloy is attacked in these environments.
      severity: moderate
      source: ati-tds
      where: Corrosion Resistance section, sulfur paragraph
    - mode: Sulfur embrittlement during annealing
      trigger: Annealing in an atmosphere with sulfur compounds, held for an extended time at the anneal temperature range
      consequence: ATI says sulfur will embrittle the material with extended exposure at the anneal temperature range.
      severity: moderate
      source: ati-tds
      where: Heat Treatment section
    - mode: Overheating during hot working
      trigger: Heating above 2150 F, or prolonged soaking at hot-working temperatures
      consequence: Special Metals says in no case should the alloy be heated above 2150 F, where permanent damage may result, and that prolonged soaking at hot-working temperatures is detrimental.
      severity: high
      source: sm-monel400
      where: Working Instructions, Heating and Pickling, Thermal Treatments
    - mode: Galvanic attack on steel in salt water
      trigger: Direct contact with steel in salt water
      consequence: Wikipedia says electrolytic action in salt water attacked a steel skeleton in contact with Monel, so the metals must be insulated.
      severity: high
      source: wiki-monel
      where: Marine applications section
    - mode: Work hardening during machining
      trigger: Machining at fast speeds or high feed rates
      consequence: Wikipedia says Monel is very difficult to machine because it work-hardens very quickly and must be turned at slow speeds and low feed rates.
      severity: low
      source: wiki-monel
      where: Properties section
  side_effects: []
  handling:
    - text: Anneal in the range of 1400 to 1800 F for short times, in an atmosphere as free of sulfur compounds as possible (ATI).
      source: ati-tds
      where: Heat Treatment section
    - text: Stress relief at 1000 to 1200 F for 1 hour, followed by slow cooling, is strongly recommended as a precaution against stress-corrosion cracking in certain environments (Special Metals).
      source: sm-monel400
      where: Working Instructions, Heating and Pickling, Thermal Treatments
    - text: ATI gives a low-temperature stress relief of about 575 F (300 C) for 1 to 3 hours on cold-deformed material.
      source: ati-tds
      where: Heat Treatment section
    - text: Stress equalizing holds cold-worked material at about 575 F for about 3 hours (Special Metals).
      source: sm-monel400
      where: Working Instructions, Heating and Pickling
    - text: Hot form at 1200 to 2150 F, with heavy reductions at 1700 to 2150 F, and never heat above 2150 F (Special Metals).
      source: sm-monel400
      where: Working Instructions, Hot Forming
    - text: Weld with MONEL Filler Metal 60 (AWS A5.14/ERNiCu-7) or MONEL Welding Electrode 190 (AWS A5.11/ENiCu-7) (Special Metals).
      source: sm-monel400
      where: Welding Products list
    - text: ATI says no preheat or post-weld heat treatment is generally required, and the joint must be free of lubricants, paint and scale.
      source: ati-tds
      where: Weldability section
    - text: Machine at slow speeds and low feed rates, because the alloy work-hardens quickly (Wikipedia).
      source: wiki-monel
      where: Properties section
  mitigations:
    - text: Stress relieve after cold working, as Special Metals recommends, as a precaution against stress-corrosion cracking in certain environments.
      source: sm-monel400
      where: Working Instructions, Heating and Pickling, Thermal Treatments
    - text: Design for flowing rather than stagnant seawater, since Special Metals reports very low corrosion rates in flowing seawater and crevice and pitting in stagnant conditions.
      source: sm-monel400
      where: Corrosion Resistance section, first paragraph
    - text: Insulate Monel from steel in salt water to avoid galvanic attack (Wikipedia).
      source: wiki-monel
      where: Marine applications section
    - text: Anneal in a sulfur-free atmosphere, since sulfur embrittles the alloy during extended annealing (ATI).
      source: ati-tds
      where: Heat Treatment section
uses:
  - application: propulsion-and-tanks
    device: Gasoline and fresh water tanks
    example: Special Metals lists gasoline and fresh water tanks among the typical applications of alloy 400, together with crude petroleum stills, process vessels and piping.
    source: sm-monel400
    where: Introduction, typical applications list
  - application: structures
    device: Marine fixtures and fasteners
    example: Special Metals lists marine fixtures and fasteners among the typical applications of alloy 400.
    source: sm-monel400
    where: Introduction, typical applications list
  - application: thermal-control
    device: Boiler feedwater heaters, heat exchangers and deaerating heaters
    example: Special Metals lists boiler feedwater heaters and other heat exchangers, and deaerating heaters, among the typical applications of alloy 400.
    source: sm-monel400
    where: Introduction, typical applications list
  - application: mechanisms
    device: Valves, pumps, and pump and propeller shafts
    example: Special Metals lists valves and pumps, and pump and propeller shafts, among the typical applications of alloy 400. Wikipedia says Monel is used for pump shafts and seawater valves.
    source: sm-monel400
    where: Introduction, typical applications list; Wikipedia, Marine applications section
  - application: structures
    device: Frames and skins of experimental rocket planes
    example: Wikipedia says Monel metal was used in bulk in aircraft construction, including the frames and skins of experimental rocket planes such as the X-15. The article calls it Monel metal and does not name the grade.
    source: wiki-monel
    where: Aerospace applications section
supply:
  - subject: Nickel
    abundance: Globally, nickel resources have been estimated to contain more than 350 million tons of nickel (USGS)
    producers:
      - country: Indonesia
        share_percent: 66.7
        year: 2025
      - country: Philippines
        share_percent: 6.9
        year: 2025
      - country: Russia
        share_percent: 5.1
        year: 2025
      - country: Canada
        share_percent: 3.6
        year: 2025
    recycling: In 2025, nickel recovered from scrap accounted for approximately 60% of apparent consumption (USGS).
    substitutes:
      - Titanium alloys can substitute for nickel or nickel-base alloys in corrosive environments (USGS).
    source: usgs-mcs2026-nickel
    where: World Mine Production and Reserves table, 2025e column (world total 3,900,000 t); shares calculated by Space Mushroom from the printed tonnages; Recycling; Substitutes; World Resources
  - subject: Copper
    abundance: 'World resources: identified resources contain 1.5 billion tons of unextracted copper (2.1 billion tons including past production), and undiscovered resources an estimated 3.5 billion tons (USGS, 2015 assessment)'
    producers:
      - country: Chile
        share_percent: 23
        year: 2025
      - country: Congo (Kinshasa)
        share_percent: 13.9
        year: 2025
      - country: Peru
        share_percent: 11.7
        year: 2025
      - country: China
        share_percent: 7.8
        year: 2025
    recycling: Old scrap provided an estimated 160,000 tons of copper in 2025, and new scrap an estimated 760,000 tons; copper recovered from scrap contributed about 30% of the U.S. copper supply (USGS).
    substitutes:
      - Aluminum substitutes for copper in automobile radiators, cooling and refrigeration tube, electrical equipment and power cable. Titanium and steel are used in heat exchangers (USGS).
    critical_lists:
      - list: US Final 2025 List of Critical Minerals (copper added, 90 FR 50494)
        listed: true
    source: usgs-mcs2026-copper
    where: World Mine and Refinery Production table, mine production 2025e (world total 23,000 thousand t, rounded); shares calculated by Space Mushroom; Events, Trends, and Issues (critical minerals); Recycling; Substitutes; World Resources
media: []
documents:
  - title: MONEL alloy 400 datasheet, Special Metals Corporation (publication SMC-053, February 2005)
    type: datasheet
    url: https://www.specialmetals.com/documents/technical-bulletins/monel-alloy-400.pdf
    year: 2005
  - title: ATI 400 Technical Data Sheet, version 1 (2/18/2014)
    type: datasheet
    url: https://www.atimaterials.com/Products/Documents/datasheets/nickel-cobalt/nickel-based/ati_400_tds_en_v1.pdf
    year: 2014
  - title: ATI 400 Nickel-Based Alloy product page (plate minimums and specifications)
    type: datasheet
    url: https://www.atimaterials.com/Products/ati-400
  - title: Monel, Wikipedia English article (read in this run)
    type: database
    url: https://en.wikipedia.org/wiki/Monel
  - title: ESPI Metals technical data, nickel-copper alloys (Alloy 400 entry)
    type: datasheet
    url: http://www.espimetals.com/index.php/technical-data/165-nickel-copper-monel-alloys
  - 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: Copper'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-copper.pdf
    year: 2026
  - title: PubChem nickel (CID 935), GHS classification (PUG View JSON)
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/935/JSON?heading=GHS+Classification
  - title: PubChem copper (CID 23978), GHS classification (PUG View JSON)
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23978/JSON?heading=GHS+Classification
gaps:
  - No corrosion rate, critical pitting temperature, ASTM G48 result or stress-corrosion threshold was printed in the sources read. The seawater, hydrofluoric-acid and stress-corrosion entries are qualitative.
  - No fatigue value is recorded. Special Metals Tables 18 and 19 (fatigue strength of rod and of sheet) and the S-N figures were not transcribed.
  - Low-temperature tensile (Table 6), Charpy impact (Tables 13 to 17), torsion (Table 7), compression (Table 8), shear (Tables 9 and 10), tear (Table 11) and bearing (Table 12) data were not transcribed.
  - No numeric maximum service temperature is printed. Special Metals names ASME allowable-stress ranges up to 800 F (Section III) and 900 F (Section VIII Division 1) without stress values, and ATI says creep resistance should be considered above about 650 F (343 C), so max_service_temp is left out.
  - No numeric minimum service temperature is printed. Wikipedia says the alloy does not undergo a ductile-to-brittle transition even when cooled to the temperature of liquid hydrogen, but gives no number, so min_service_temp is left out.
  - Special Metals Table 4 values are composite ranges for various product sizes and are not specification values (footnote a). ATI values are typical, and the ATI product-page minimums are for plate only.
  - The ATI product-page bar composition table places its nickel value in a column that does not match the other tables, so no bar composition was used. Composition comes from Special Metals Table 1 and the ATI plate table.
  - 'Densities differ by source: 8.80 g/cm3 (Special Metals), 8.83 g/cm3 (ATI data sheet) and 8.84 g/cm3 for plate (ATI product page). The first two are recorded; the product-page value is left out to avoid a third density row.'
  - electrical_conductivity (about 34 percent IACS, Wikipedia) is not in property-canon.yaml, so it uses a snake_case name until a canonical entry exists. Wikipedia gives no temperature or condition for it.
  - No product safety data sheet for solid Monel 400 was read. The hazard entries rely on the PubChem records for nickel (about 63 percent of the alloy) and copper (28.0 to 34.0 percent), which describe the metals, not the alloy.
  - The USGS 2026 nickel summary mentions an executive order on seabed deposits for critical minerals such as nickel but prints no critical-mineral list status, so nickel has no critical_lists entry. Copper is on the US Final 2025 List of Critical Minerals (USGS copper summary).
  - The ASTM, ASME and AMS standard texts are paywalled and were not read. Designations come from the Special Metals product list (ASTM, ASME, AMS, BS, DIN and QQ numbers), the ATI product page and data sheet, and the Wikipedia table.
  - NiCu30Fe is not printed in the Special Metals or ATI datasheets. It appears in the Wikipedia citation title for Monel 400 (NiCu30Fe, 2.4360, N04400, NA13), and that citation is the only source for the EN name.
  - Monel K-500 is a different, age-hardened alloy, and Monel 405 (R-405, the free-machining grade) is a different grade. Their codes are left out. The Special Metals Tables 2 and 3 values are printed for MONEL alloy 400, and footnote a says they also apply to R-405.
  - The Special Metals datasheet is publication SMC-053 dated February 2005, and the ATI data sheet is version 1 dated 2/18/2014. Values may have been revised since.
  - Copper and nickel shares are calculated by Space Mushroom from the printed USGS tonnages, not printed as shares.
  - The ESPI Metals technical data page is a supplier summary and is used only for a qualitative corrosion statement.
sources:
  sm-monel400:
    title: MONEL alloy 400 datasheet, Special Metals Corporation
    id: Special Metals Corporation, publication SMC-053 (Feb 2005)
    url: https://www.specialmetals.com/documents/technical-bulletins/monel-alloy-400.pdf
    year: 2005
    kind: datasheet
    license: Special Metals terms (cited, not reproduced)
  ati-tds:
    title: ATI 400 Technical Data Sheet (UNS N04400)
    id: ATI Allegheny Technologies, version 1 (2/18/2014)
    url: https://www.atimaterials.com/Products/Documents/datasheets/nickel-cobalt/nickel-based/ati_400_tds_en_v1.pdf
    year: 2014
    kind: datasheet
    license: ATI terms (cited, not reproduced)
  ati-page:
    title: ATI 400 Nickel-Based Alloy product page
    id: ATI product page, read in this run (2026-10-24)
    url: https://www.atimaterials.com/Products/ati-400
    kind: web
    license: ATI terms (cited, not reproduced)
  wiki-monel:
    title: Monel
    id: Wikipedia, English article (read in this run, 2026-10-24)
    url: https://en.wikipedia.org/wiki/Monel
    kind: web
    license: CC BY-SA 4.0
  espi-alloy400:
    title: ESPI Metals technical data, nickel-copper alloys
    id: ESPI Metals, Alloy 400 entry, read in this run (2026-10-24)
    url: http://www.espimetals.com/index.php/technical-data/165-nickel-copper-monel-alloys
    kind: web
    license: Supplier page (cited, not reproduced)
  usgs-mcs2026-nickel:
    title: 'Mineral Commodity Summaries 2026: Nickel'
    id: USGS, Mineral Commodity Summaries 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf
    year: 2026
    kind: report
    license: US Government work (public domain)
  usgs-mcs2026-copper:
    title: 'Mineral Commodity Summaries 2026: Copper'
    id: USGS, Mineral Commodity Summaries 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-copper.pdf
    year: 2026
    kind: report
    license: US Government work (public domain)
  pubchem-nickel:
    title: Nickel, PubChem CID 935, GHS classification (aggregated ECHA C&L notifications)
    id: PubChem CID 935
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/935/JSON?heading=GHS+Classification
    kind: database
    license: PubChem (NIH, public domain)
  pubchem-copper:
    title: Copper, PubChem CID 23978, GHS classification (aggregated ECHA C&L notifications)
    id: PubChem CID 23978
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23978/JSON?heading=GHS+Classification
    kind: database
    license: PubChem (NIH, public domain)
license: CC-BY-4.0
updated: '2026-10-24'
review:
  status: draft
  method: assistant
  checked_values: 28
  unreachable: 0
  caveats: 17
  note: Written by an AI assistant on 2026-10-24 from the Special Metals MONEL alloy 400 datasheet (SMC-053, 2005), the ATI 400 data sheet (2014) and product page, the Wikipedia Monel article, ESPI Metals technical data, USGS MCS 2026 nickel and copper, and PubChem GHS records for nickel and copper. Every number was read from a page fetched in this run. Web search was unavailable in this run, so the pages were fetched directly. The compare link points to the Inconel 625 profile, and no value from that file was used.
story:
  recipe:
    line: Monel 400 is a single-phase nickel-copper alloy. Special Metals gives the limiting composition in weight percent, with nickel plus cobalt at least 63.0, copper 28.0 to 34.0, and iron 2.5 maximum, manganese 2.0 maximum, silicon 0.5 maximum, carbon 0.3 maximum and sulfur 0.024 maximum. Nickel and copper are mutually soluble in all proportions, so the alloy is one solid-solution phase (Wikipedia). Special Metals says it is hardened only by cold working.
    parts:
      - name: Nickel plus cobalt
        symbol: Ni
        share_percent: 63
        share_note: minimum, nickel plus cobalt
        role: Matrix of the single-phase solid solution, with copper
        source: sm-monel400
        where: Table 1, Limiting Chemical Composition, Nickel (plus Cobalt) 63.0 min
      - name: Copper
        symbol: Cu
        share_percent: 28
        share_high: 34
        role: Mutually soluble with nickel in all proportions, so the alloy is single-phase (Wikipedia)
        source: sm-monel400
        where: Table 1, Limiting Chemical Composition, Copper 28.0 to 34.0
      - name: Iron
        symbol: Fe
        share_percent: 2.5
        share_note: 2.5 maximum
        role: Residual element, limited to 2.5 percent
        source: sm-monel400
        where: Table 1, Iron 2.5 max
      - name: Manganese
        symbol: Mn
        share_percent: 2
        share_note: 2.0 maximum
        role: Residual element, limited to 2.0 percent
        source: sm-monel400
        where: Table 1, Manganese 2.0 max
      - name: Silicon
        symbol: Si
        share_percent: 0.5
        share_note: 0.5 maximum
        role: Residual element, limited to 0.5 percent
        source: sm-monel400
        where: Table 1, Silicon 0.5 max
      - name: Carbon
        symbol: C
        share_percent: 0.3
        share_note: 0.3 maximum
        role: Residual element, limited to 0.3 percent
        source: sm-monel400
        where: Table 1, Carbon 0.3 max
      - name: Sulfur
        symbol: S
        share_percent: 0.024
        share_note: 0.024 maximum
        role: Residual element, limited to 0.024 percent
        source: sm-monel400
        where: Table 1, Sulfur 0.024 max
  risk_groups:
    - title: For people
      level: 2
      verdict: Metal flagged by nickel and copper records; no alloy SDS
      lead: No safety data sheet for solid Monel 400 was read. The flags come from PubChem records for nickel (about 63 percent of the alloy) and copper (28.0 to 34.0 percent).
      points:
        - label: Nickel record
          line: PubChem aggregated nickel GHS lists skin sensitisation (H317, 99.9 percent of reports), suspected cancer (H351, 72.9 percent) and organ damage from prolonged exposure (H372, 99.7 percent).
        - label: Copper record
          line: PubChem aggregated copper GHS lists very toxic to aquatic life (H400, 43.1 percent) and very toxic with long-lasting effects (H410, 18.8 percent).
    - title: If a part sees the wrong conditions
      lead: These results come from the datasheets and the Wikipedia article, not from field incidents.
      points:
        - label: Stagnant seawater
          line: Special Metals says stagnant seawater induces crevice and pitting corrosion, although flowing seawater gives very low corrosion rates.
        - label: Caustic at high stress
          line: ATI says high temperature, high stress and high caustic concentration have produced caustic stress-corrosion cracking.
        - label: Overheating
          line: Special Metals says the alloy must not be heated above 2150 F, where permanent damage may result.
    - title: Handling and heat treatment
      points:
        - label: Stress relief
          line: Stress relief at 1000 to 1200 F for 1 hour, then slow cooling, is strongly recommended against stress-corrosion cracking in certain environments (Special Metals).
        - label: Hot forming
          line: Hot forming runs from 1200 to 2150 F, with heavy reductions at 1700 to 2150 F (Special Metals).
  why: Monel 400 comes from a nickel-copper ore developed in the early twentieth century, whose nickel and copper were in about the ratio now specified for the alloy (ATI). Special Metals says it combines high strength and toughness with excellent resistance to many corrosive environments, and its name is a trademark now held by Special Metals (Wikipedia). Marine and chemical processing use it because it resists seawater and reducing acids (Special Metals).
  uses:
    - where: Marine and chemical service
      line: Special Metals names valves and pumps, pump and propeller shafts, marine fixtures and fasteners, chemical processing equipment, and crude petroleum stills, process vessels and piping as typical applications.
    - where: Heat exchangers and boiler feedwater heaters
      line: Boiler feedwater heaters, other heat exchangers and deaerating heaters are typical applications (Special Metals).
    - where: Fuel and water tanks
      line: Gasoline and fresh water tanks are typical applications (Special Metals).
    - where: Aircraft structures, historical
      line: Wikipedia says Monel metal was used in bulk in aircraft construction, including the frames and skins of experimental rocket planes such as the X-15, though the article does not name the grade.
  can_do:
    - label: Seawater
      line: Very low corrosion rates in flowing seawater (Special Metals), and Wikipedia says it resists rapidly flowing seawater.
    - label: Hydrofluoric acid
      line: Exceptional resistance to hydrofluoric acid in all concentrations up to the boiling point (Special Metals).
    - label: Strength in the annealed condition
      line: Annealed rod and bar give 75 to 90 ksi tensile and 25 to 50 ksi yield, and annealed hot-rolled plate gives 70 to 85 ksi tensile (Special Metals Table 4, composite ranges).
    - label: Stiffness
      line: Tension modulus is 26.0 times 10^3 ksi (Special Metals Table 2), and ATI gives 180 GPa for annealed plate, sheet and strip.
    - label: Low temperature
      line: Wikipedia says the alloy does not undergo a ductile-to-brittle transition even when cooled to the temperature of liquid hydrogen.
  compare: Compare with [Inconel 625](/profiles/inconel-625/), the chromium-bearing nickel alloy on this site. Monel 400 has no chromium in its limiting composition, and its composition is nickel with 28.0 to 34.0 percent copper (Special Metals Table 1). Monel K-500 is a different, age-hardened alloy and is not covered by this profile.
  compare_rows:
    - label: Density
      benchmark: density
      scope: material
    - label: Stiffness
      benchmark: elastic_modulus
      scope: material
    - label: Melting range
      benchmark: melting_point
      scope: material
  handling:
    - Anneal in the range of 1400 to 1800 F for short times, in an atmosphere as free of sulfur compounds as possible (ATI).
    - Stress-relieve at 1000 to 1200 F for 1 hour and cool slowly, which Special Metals strongly recommends as a precaution against stress-corrosion cracking in certain environments.
    - Hot form at 1200 to 2150 F, with heavy reductions at 1700 to 2150 F, and never heat above 2150 F (Special Metals).
    - Weld with MONEL Filler Metal 60 or MONEL Welding Electrode 190 (Special Metals). ATI says no preheat or post-weld heat treatment is generally needed.
    - Machine at slow speeds and low feed rates, because the alloy work-hardens quickly (Wikipedia).
  good_for:
    - Seawater and marine parts that need strength with corrosion resistance, such as valves, pump and propeller shafts and fasteners (Special Metals).
    - Hydrofluoric-acid service, including the reacting section of alkylation units (Wikipedia; Special Metals).
    - Chemical processing in reducing acids, and heat exchangers and boiler feedwater heaters (Special Metals).
  watch_out:
    - Stagnant seawater can cause crevice and pitting corrosion, although flowing seawater gives very low corrosion rates (Special Metals).
    - Caustic stress-corrosion cracking can occur at high temperature, high stress and high caustic concentration (ATI).
    - Strength ranges are composites for various product sizes and are not specification values (Special Metals Table 4).
    - Some heats are magnetic at room temperature and others are not, because the Curie temperature sits near room temperature (Special Metals Table 2).
    - Galvanic attack on steel in salt water (Wikipedia).
    - The corrosion entries are qualitative. No corrosion rate or test number was read in this run.
  verdict: Monel 400 is a nickel-copper alloy for seawater, chemical and hydrofluoric-acid service. Its annealed strength is modest, so state the temper on every design, design for flowing rather than stagnant seawater, and stress-relieve where stress-corrosion cracking is a concern.