Monel 400
UNS N04400
Overview
A nickel-copper alloy (≈ 67% Ni, 23% Cu) with exceptional resistance to seawater, hydrofluoric acid, and caustic alkalis. Known for its high strength and toughness across a wide temperature range from cryogenic to 480°C. The classic marine engineering alloy — used in shipbuilding, offshore, and desalination for over 100 years.
Chemical Composition (wt%)
| Element | Min | Max |
|---|---|---|
| Ni (Nickel) | 63 | — |
| Cu (Copper) | 28 | 34 |
| Fe (Iron) | — | 2.5 |
| Mn (Manganese) | — | 2 |
| C (Carbon) | — | 0.3 |
| Si (Silicon) | — | 0.5 |
| S (Sulfur) | — | 0.024 |
Mechanical Properties
| Property | Value | Condition |
|---|---|---|
| Tensile Strength | ≥ 483 MPa (70 ksi) | — |
| Yield Strength (0.2%) | ≥ 172 MPa (25 ksi) | — |
| Elongation | ≥ 35% | — |
| Hardness | ≤ 25 HRC | annealed |
| Density | 8.80 g/cm³ | — |
Physical Properties
| Property | Value |
|---|---|
| Melting Range | 1300 – 1350 °C |
| Thermal Conductivity | 21.8 W/m·K (at 20°C) |
| Max Service Temp | 480°C |
Corrosion Resistance
Exceptional resistance to seawater and marine atmospheres — the benchmark alloy for saltwater service. Outstanding resistance to hydrofluoric acid at all concentrations up to the boiling point. Excellent resistance to caustic alkalis (NaOH, KOH) even at elevated temperatures. Good resistance to sulfuric acid in deaerated conditions. Susceptible to stress corrosion cracking in the presence of mercury or moist ammonia.
Typical Applications
Related Standards
Available Products in This Material
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