Materials / Nickel alloy
Monel 400
- UNS
- N04400
- W.Nr
- 2.4360
- EN
- NiCu30Fe
A solid-solution nickel-copper alloy, essentially unchanged in composition for over a century, and still the default for seawater and hydrofluoric acid service.
Composition
| Element | Min | Max |
|---|---|---|
| Ni | 63.0 | — |
| Cu | 28.0 | 34.0 |
| Fe | — | 2.5 |
| Mn | — | 2.0 |
| C | — | 0.3 |
| Si | — | 0.5 |
| S | — | 0.024 |
Per cent by weight, to the governing standard.
- Ni69.0
- Cu31.0
Per cent by weight, at the midpoint of each specified window. Elements given only as a maximum have no midpoint to take, so they sit inside the balance rather than being estimated; trace elements below 0.5 % are not shown. Indicative only; the composition table above and the governing standard are what define the limits.
Mechanical
- Tensile strength, min
- 480 MPa
- Yield strength (0.2%), min
- 195 MPa
- Elongation, min
- 35 %
- Condition
- Annealed
Standards by form
| Plate, sheet & strip | ASTM B127 | |
|---|---|---|
| Pipe & tube | ASTM B165 | |
| Bar & rod | ASTM B164 | |
| Fittings | ASTM B366 |
Where it is specified
- Seawater, brackish water and marine service — resists erosion and cavitation
- Hydrofluoric acid, alkalis, and reducing conditions
- Retains strength and toughness down to cryogenic temperatures
Nickel costs four times copper, and the ratio is the alloy
Nickel is roughly four times the price of copper, so the economic incentive runs one way: push nickel toward the 63 % floor and copper toward the 34 % ceiling. A heat sitting outside the ratio still looks like Monel and still machines like Monel, and it corrodes faster in exactly the seawater service it was bought for.
What we specify and check
- PMI specified on the delivered heat, reading the Ni:Cu ratio rather than nickel alone
- Iron verified against the 2.5 % maximum
- Sulphur checked where hot working or welding is planned
- Certificate matched to the heat number in the crate
We commission an accredited independent laboratory to test the heat before the material leaves China. You will receive that report unedited, whether it passes or not.
Request Monel 400
Tell us the form, dimensions and service conditions. We reply with availability, indicative landed price, lead time and the test regime we would specify for your application.
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