Monel 400 · UNS N04400 · W. Nr. 2.4360 · NiCu30Fe · Alloy 400
Monel 400 (N04400): composition, properties, fittings and flanges
Monel 400 (UNS N04400, W. Nr. 2.4360) is a nickel-copper alloy with 63 % nickel minimum and 28-34 % copper, strengthened only by solid solution. It is one of very few structural alloys that resists hydrofluoric acid at all concentrations up to the boiling point, plus hydrofluorosilicic acid, anhydrous HF and fluorine gas,…
- UNS
- N04400
- W. Nr.
- 2.4360
- Density
- 8.83 g/cm³ (0.319 lb/in³)
- Key strength
- 480 MPa / 70 ksi
Identification and standards
| Short form | Monel 400 · UNS N04400 · W. Nr. 2.4360 · NiCu30Fe · Alloy 400 |
|---|---|
| Classification | Solid-solution nickel-copper alloy |
| UNS | N04400 |
| Werkstoff number | 2.4360 |
| Material family | Monel Alloys |
Chemical composition
| Element | Composition (wt %) | Why it is there |
|---|---|---|
| Nickel + Cobalt (Ni+Co) | 63.0 min | Matrix, caustic and HF resistance |
| Copper (Cu) | 28.0 - 34.0 | Seawater and reducing acid resistance |
| Iron (Fe) | 2.5 max | - |
| Manganese (Mn) | 2.00 max | - |
| Silicon (Si) | 0.50 max | - |
| Carbon (C) | 0.30 max | - |
| Sulphur (S) | 0.024 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 bar, ASTM B164) | 480 MPa / 70 ksi |
|---|---|
| 0.2 % yield strength, min | 170 MPa / 25 ksi |
| Elongation in 2 in, min | 35 % |
| Typical hardness, annealed | 110 - 170 HB |
| Typical hardness, hot finished | 140 - 200 HB |
| Usable temperature range | -100 °C to 480 °C |
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 | 8.83 g/cm³ (0.319 lb/in³) |
|---|---|
| Melting range | 1300 - 1350 °C (2370 - 2460 °F) |
| Modulus of elasticity | 179 GPa (26 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 |
| Electrical resistivity at 20 °C | 0.51 µΩ·m |
| Curie temperature | Approximately 21 °C for the annealed alloy |
Specifications by product form
| Bar / rod / wire | ASTM B164 / ASME SB-164 |
|---|---|
| Plate / sheet / strip | ASTM B127 / ASME SB-127 |
| Seamless pipe & tube | ASTM B165 / ASME SB-165, ASTM B163 (condenser tube) |
| Forgings & flanges | ASTM B564 / ASME SB-564 (UNS N04400) |
| Butt weld fittings | ASTM B366 / ASME SB-366 (WP400) |
| Welding consumables | ERNiCu-7 wire (AWS A5.14), ENiCu-7 electrode (AWS A5.11) |
| UNS / EN / China | UNS N04400 · EN NiCu30Fe · W. Nr. 2.4360 · GB NCu28-2.5-1.5 |
Product forms available
Hangbo supplies this grade in the following forms. Sizes outside the listed range can often be produced to order.
- Seamless pipe and tube including condenser tube
- Plate, sheet and strip
- Forged flanges to ASME B16.5 Class 150-2500
- Elbows, tees, reducers, caps and stub ends to ASME B16.9
- Pump shafts, valve trim and fasteners
Typical applications
- Marine piping, pump shafts, propellers, strainer baskets and sea water valves
- HF alkylation units, anhydrous HF piping and fluorine handling equipment
- Caustic soda evaporators, rayon coagulation baths and soap plant equipment
- Crude oil distillation columns, sour water strippers and refinery overhead condensers
- Feedwater heaters, steam generator and boiler feedwater systems
- Nuclear waste processing and spent fuel storage equipment
Welding, forming and machining
- Welding
- Weld readily by GTAW, GMAW, SMAW and SAW with ERNiCu-7 filler. Cleanliness is critical - remove all oil, paint, marking crayons and shop dirt, because sulphur and lead cause hot cracking.
- Hot forming
- Hot work between 1200 °C and 950 °C followed by annealing at 760-925 °C. Avoid heating in sulphur-bearing atmospheres.
- Machining
- Machines best in the annealed or stress-relieved condition. Use low-to-medium cutting speeds, positive rake tools and heavy-duty cutting fluids.
- Annealing
- Anneal at 760-925 °C for stress relief and grain refinement, cooling in air or water according to section size.
Buy Monel 400 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.