Monel 401 · UNS N04401
Monel 401 (N04401): composition, properties, fittings and flanges
Monel 401 (N04401) is Low-nickel nickel-copper electronic alloy. Monel 401 is specified at Nickel 43.0 - 47.0, Copper Balance, Cobalt 0.25 max. Monel 401 is the electrical and electronic grade of the Monel family: about 45 % nickel with copper, formulated for controlled resistivity and low magnetic permeability in lead frames…
- UNS
- N04401
- W. Nr.
- -
- Density
- 8.91 g/cm³ (0.322 lb/in³)
- Key strength
- 480 MPa / 70 ksi
Identification and standards
| Short form | Monel 401 · UNS N04401 |
|---|---|
| Classification | Low-nickel nickel-copper electronic alloy |
| UNS | N04401 |
| Werkstoff number | - |
| Material family | Monel Alloys |
Chemical composition
| Element | Composition (wt %) | Why it is there |
|---|---|---|
| Nickel (Ni) | 43.0 - 47.0 | Matrix and resistivity control |
| Copper (Cu) | Balance | Matrix |
| Iron (Fe) | 0.75 max | Residual |
| Manganese (Mn) | 1.25 max | Deoxidation |
| Carbon (C) | 0.10 max | - |
| Silicon (Si) | 0.25 max | - |
| Sulphur (S) | 0.015 max | Machinability and hot ductility |
| Cobalt (Co) | 0.25 max | - |
Note Single figures are maximum limits unless shown as a range. Always confirm against the heat-specific EN 10204 3.1 certificate supplied with your order.
Mechanical properties
| Tensile strength, min (annealed) | 480 MPa / 70 ksi |
|---|---|
| 0.2 % yield strength, min | 170 MPa / 25 ksi |
| Elongation in 2 in, min | 35 % |
| Typical hardness, annealed | 110 - 160 HB |
| Electrical resistivity, typical | About 49 µΩ·cm |
Warning Values depend on product form, section thickness and heat treatment. Larger sections generally achieve lower strength than thin product; always design against the applicable code allowable stress rather than these figures.
Physical properties
| Density | 8.91 g/cm³ (0.322 lb/in³) |
|---|---|
| Melting range | 1280 - 1350 °C (2335 - 2460 °F) |
| Modulus of elasticity | 179 GPa (26.0 x 10⁶ psi) |
| Thermal conductivity at 20 °C | 21.8 W/m·K |
| Mean coefficient of thermal expansion, 20-100 °C | 13.9 µm/m·°C |
| Specific heat capacity | 410 J/kg·K |
Specifications by product form
| Forgings & flanges | ASTM B564 family (UNS N04401) |
|---|---|
| Butt weld fittings | To order against ASTM B366 chemistry |
| Seamless pipe & tube | To order |
| Plate / sheet / strip | ASTM B127 family |
| Bar / rod | ASTM B164 |
| Welding consumables | ERNiCu-7 for Monel family joints |
| UNS / EN / China | UNS N04401 |
Product forms available
Hangbo supplies this grade in the following forms. Sizes outside the listed range can often be produced to order.
- Forged flanges blanks and finished flanges to ASME B16.5, B16.47 Series A/B and B16.36
- Butt weld elbows, tees, reducers, caps and stub ends to ASME B16.9 and MSS SP-43
- Seamless pipe and tube to the applicable ASTM / ASME pipe specification
- Forged rings, discs and hubs machined to your drawing
Typical applications
- Electronic lead frames, contacts and resistance elements
- Instrument and thermostat components
- Welding and brazing filler where resistivity matters
- Specialty marine hardware needing low permeability
Welding, forming and machining
- Welding
- Weld with ERNiCu-7 filler by GTAW. Clean thoroughly; copper alloys conduct heat away quickly so preheat the heavier sections.
- Heat treatment
- Anneal at 760 - 925 °C and cool as required by the specified temper.
- Hot and cold forming
- Hot work in the range stated by the mill for this grade, then re-solution or re-age before final machining so that the delivered condition matches the certificate.
- Machining
- Machine with sharp carbide or high-speed steel tooling, positive rake, constant feed and ample coolant. Never dwell - the surface work-hardens quickly.
Buy Monel 401 from Hangbo
Material is supplied with full heat-number traceability, solution annealing or ageing performed under calibrated furnace control, and an EN 10204 3.1 certificate covering chemical analysis, mechanical properties, heat treatment records and the agreed NDT scope. Positive material identification and third party inspection and test reports from SGS are available for critical service.