Nickel Alloy Monel 400
UNS N04400 · ASTM B127 · EN 2.4360, NiCu30Fe · GB NCu30 · BS NA13
Monel 400 (UNS N04400, 2.4360, ASTM B127) is a solid-solution nickel-copper alloy with excellent resistance to seawater and hydrofluoric acid and good strength retention across a wide temperature range up to 480 °C.
Values for the O condition
Monel 400 tempers and conditions
Monel 400 is supplied in 5 conditions, soft to hard. O is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ODefault Annealed | Standard stocked condition for plate, sheet, tube and welded fabrications where maximum formability and corrosion performance are wanted. | 240 | 550 | 45 | 125 HB | — |
hot-rolled / hot-worked bar and plate, as-worked | Economical condition for large-section bar, forgings and as-rolled plate where mid-range strength is acceptable. | 310 | 585 | 40 | 150 HB | 3.2 % IACS |
cold-worked bar, rod and tube (as-drawn) | Choose for shafting, fasteners and machined parts needing higher yield strength, better surface finish and improved chip control. | 480 | 690 | 25 | 200 HB | — |
cold-worked then 275–345 °C stress relief | Use where cold-drawn strength must be kept but residual stress (distortion on machining, SCC risk) has to be reduced. | 550 | 700 | 22 | 215 HB | 3.2 % IACS |
full-hard cold-rolled sheet/strip | Spring-temper strip and diaphragms where high yield strength and stiffness in thin section outweigh formability. | 690 | 830 | 6 | 25 HRC | 3.2 % IACS |
What is Monel 400?
Monel 400 (UNS N04400, 2.4360, ASTM B127) is a solid-solution nickel-copper alloy with excellent resistance to seawater and hydrofluoric acid and good strength retention across a wide temperature range up to 480 °C. Annealed material gives 240 MPa yield, 550 MPa tensile and 45% elongation at 125 HB, and it is common as sheet, plate, bar and cold-drawn rod for pump, valve and heat-exchanger parts. Weldability and cold formability are good (scores 82 and 85), but machinability is low (30) because the alloy work-hardens rapidly. For roughly double the strength in the same environments, step up to age-hardened Monel K500. Monel 400 has a density of 8.8 g/cm³ (0.318 lb/in³), heavier than 81% of nickel alloy grades. It melts at 1,300°C (2,372 °F). Monel 400 has a yield strength of 240 MPa (34.8 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 90% of nickel alloy grades. Elongation at break is 45% and the elastic modulus is 179 GPa (26 Msi).
What is Monel 400 used for?
- Seawater valve bodies and trim
- Marine pump shafts and casings
- Heat exchanger tubing and tubesheets
- Hydrofluoric acid process piping
- Feedwater heater components
- Chemical processing vessels and liners
- Offshore fasteners and hardware
Advantages
- Forms and bends easily — 85/100, better than 95% of nickel alloy grades
- Conducts heat well — 21.8 W/m·K (12.6 BTU/hr·ft·°F), better than 90% of nickel alloy grades
- Easy to machine — 30/100, better than 90% of nickel alloy grades
- Low embodied carbon — 9.5 kg CO₂/kg, better than 90% of nickel alloy grades
- High electrical conductivity — 3.2 % IACS, better than 89% of nickel alloy grades
Limitations
- Low strength — 240 MPa (34.8 ksi), worse than 90% of nickel alloy grades
- Low stiffness — 179 GPa (26 Msi), worse than 88% of nickel alloy grades
- Limited service temperature — 480°C (896 °F), worse than 82% of nickel alloy grades
Monel 400 properties
Typical room-temperature values for Monel 400-O; bars are the position among nickel alloy grades.
Physical3
Monel 400 has a density of 8.8 g/cm³ (0.318 lb/in³), heavier than 81% of nickel alloy grades. It melts at 1,300°C (2,372 °F).
Mechanical14
Monel 400 has a yield strength of 240 MPa (34.8 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 90% of nickel alloy grades. Elongation at break is 45% and the elastic modulus is 179 GPa (26 Msi).
Thermal6
Monel 400 is rated for continuous service to 480°C (896 °F). It conducts heat at 21.8 W/m·K (12.6 BTU/hr·ft·°F), better than 90% of nickel alloy grades. Thermal expansion is 13.9 µm/m·K (7.72 µin/in·°F).
Electrical3
Monel 400 conducts electricity at 3.2 % IACS, better than 89% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (78/100), better than 51% of nickel alloy grades.
Sustainability4
Producing a kilogram of Monel 400 takes about 120 MJ of energy and emits 9.5 kg of CO₂ — less than 90% of nickel alloy grades. Typical recycled content is 35%.
Manufacturability7
Monel 400's machinability is poor (30/100, better than 90% of nickel alloy grades); weldability very good (82/100); formability excellent (85/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the nickel alloy family
Yield strength against density for every nickel alloy grade FabDigit runs. Monel 400 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Monel 400
Is Monel 400 easy to machine?
Work-hardens rapidly — use rigid setups, positive-rake sharp carbide, heavy positive feed and constant engagement, moderate speed (~25–40 m/min carbide) with flood sulfurized oil; never dwell in the cut.
Can Monel 400 be welded?
Readily welded by GTAW/GMAW/SMAW with Monel Filler Metal 60 (ERNiCu-7) or Electrode 190; keep surfaces free of sulfur, lead and grease, use low heat input and no preheat, and avoid autogenous welds (add Ti-bearing filler to prevent porosity).
Can Monel 400 be formed, bent or molded?
Excellent cold formability in the annealed condition (deep drawing, spinning, bending) but high springback and fast work hardening — plan interstage anneals at 760–870 °C; hot work at 870–1175 °C and finish above 650 °C.
Manufacturability
The process limits FabDigit's quote engine applies to Monel 400. Design inside these and the part quotes instantly; outside them it routes to an engineer.
CNC machining
| Machinability | Fair30 / 100 |
|---|---|
| ISO material group | S.1 |
| Cutting speed (rough / finish) | 40 / 55 m/min |
| Minimum wall | 1.5 mm |
| Minimum internal radius | 2 mm |
| Drill depth limit | 3× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Better85 / 100 |
|---|---|
| Weldability | Better82 / 100 |
| Bendable | Yes |
Monel 400 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| NiNi + Co, minimum per ASTM B127/B164 | ≥ 63 | 66 |
| Fe | ≤ 2.5 | 1.6 |
| Mn | ≤ 2 | 1 |
| C | ≤ 0.3 | 0.15 |
| Si | ≤ 0.5 | 0.2 |
| S | ≤ 0.02 | 0.01 |
| Cubalance in practice | ≥ 28 (balance) |
What surface finishes work on Monel 400?
Pickle in nitric-hydrofluoric or bright-dip after annealing to remove the tenacious green-black oxide; takes a fine mechanical polish, accepts electroless nickel or silver plating, and needs no coating for seawater service.
Surface treatments FabDigit runs on nickel alloy parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Equivalent designations
Standards and trade names that resolve to Nickel Alloy Monel 400 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- N04400
- ASTM
- B127
- EN / DIN / Werkstoff-Nr.
- 2.4360NiCu30Fe
- BS
- NA13
- GB (China)
- NCu30
- Trade names
- Monel
How much does Monel 400 cost?
Monel 400 is a premium-cost nickel alloy ($$$), pricier than about 57% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Monel 400 — frequently asked
What is Monel 400 used for?
Monel 400 is typically used for seawater valve bodies and trim, marine pump shafts and casings, heat exchanger tubing and tubesheets, hydrofluoric acid process piping, feedwater heater components and chemical processing vessels and liners. In short: seawater-resistant nickel-copper.
What is the yield strength of Monel 400?
Monel 400 has a typical yield strength of 240 MPa (34.8 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 90% of nickel alloy grades. Strength varies by condition: see the 5 listed tempers.
Is Monel 400 easy to machine?
Not especially — machinability is rated poor (30/100, better than 90% of nickel alloy grades). Work-hardens rapidly — use rigid setups, positive-rake sharp carbide, heavy positive feed and constant engagement, moderate speed (~25–40 m/min carbide) with flood sulfurized oil; never dwell in the cut.
Can Monel 400 be welded?
Yes — weldability is rated very good (82/100). Readily welded by GTAW/GMAW/SMAW with Monel Filler Metal 60 (ERNiCu-7) or Electrode 190; keep surfaces free of sulfur, lead and grease, use low heat input and no preheat, and avoid autogenous welds (add Ti-bearing filler to prevent porosity).
What surface finishes work on Monel 400?
Pickle in nitric-hydrofluoric or bright-dip after annealing to remove the tenacious green-black oxide; takes a fine mechanical polish, accepts electroless nickel or silver plating, and needs no coating for seawater service.
Can Monel 400 be formed, bent or molded?
Excellent cold formability in the annealed condition (deep drawing, spinning, bending) but high springback and fast work hardening — plan interstage anneals at 760–870 °C; hot work at 870–1175 °C and finish above 650 °C.
What is the maximum service temperature of Monel 400?
Monel 400 is rated for continuous use to about 480°C (896 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does Monel 400 cost?
Monel 400 is a premium-cost nickel alloy ($$$), pricier than about 57% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in Monel 400?
Yes — Monel 400 is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM B127 — Nickel-Copper Alloy Plate, Sheet and Strip — ASTM International (2019)
- ASTM B164 — Nickel-Copper Alloy Rod, Bar and Wire — ASTM International (2020)
- MONEL alloy 400 Technical Bulletin — Special Metals Corporation (2005)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials — ASM International (2005)
- GB/T 15007 / NCu30 — SAC (2017)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.