Monel® 400 (UNS N04400)
Nickel-Copper Alloy
What Is Monel® 400?
Monel® 400 (UNS N04400) is a solid-solution nickel-copper alloy known for excellent corrosion resistance in a wide range of reducing environments and outstanding performance in seawater. It maintains good strength and ductility from sub-zero temperatures up to about 1000°F (538°C), and unlike many alloys does not undergo a ductile-to-brittle transition at cryogenic temperatures.
Because Monel 400 is solid-solution strengthened, it cannot be hardened by heat treatment; mechanical strength is increased through cold work. The alloy is one of the few materials that can be used in hydrofluoric acid service across all concentrations and is highly resistant to chloride stress corrosion cracking.
Monel 400 has a long, proven track record in marine, chemical processing, and oil and gas applications, where its combination of corrosion resistance, strength, and fabricability provides reliable, long-term service.
Monel® 400 Standards and Designations
Common Names & Cross-References
|
Designation |
Value |
|---|---|
| Trade Names | Monel® 400, Alloy 400, Monel |
| UNS | N04400 |
| German (W.Nr. / DIN) | 2.4360 / 2.4361 — NiCu30Fe |
| British Standard | BS 3076 NA13 |
| French (AFNOR) | NU30 |
| EN (Europe) | NiCu30Fe |
| Federal | QQ-N-281 |
Properties of Monel® 400
Monel® 400 Chemical Composition
|
Element |
Composition (%) |
|---|---|
| Nickel (Ni) + Cobalt | 63.0 min |
| Copper (Cu) | 28.0 – 34.0 |
| Iron (Fe) | 2.5 max |
| Manganese (Mn) | 2.0 max |
| Silicon (Si) | 0.5 max |
| Carbon (C) | 0.3 max |
| Sulfur (S) | 0.024 max |
Typical Mechanical Properties (Annealed)
|
Property |
Typical |
Spec Min |
|---|---|---|
| Tensile Strength | 82 ksi (565 MPa) | 70 ksi |
| Yield Strength (0.2%) | 32 ksi (220 MPa) | 25 ksi |
| Elongation (in 2 in.) | 48% | 35% |
| Hardness | Rockwell B 75 | B 90 max |
About Monel® 400
Key Features & Advantages
- Excellent corrosion resistance in seawater and marine environments
- Outstanding performance in hydrofluoric acid — perhaps the most resistant commercially available alloy
- Highly resistant to chloride stress corrosion cracking
- Good strength and ductility from cryogenic to elevated temperatures
- No ductile-to-brittle transition at cryogenic temperatures
- Strong fabrication and forming characteristics
- Slightly magnetic at room temperature
Common Applications of Monel 400®
- Marine components — pump shafts, propeller shafts, fittings, fasteners
- Seawater handling systems, valves, and piping
- Heat exchangers and condenser components
- Hydrofluoric acid production and handling equipment
- Chemical processing vessels and piping
- Oil and gas downhole and surface hardware
- Crude petroleum stills and process vessels
Primary Markets Served
- Marine & Offshore
- Chemical Processing
- Oil & Gas
- Power Generation
- Defense & Naval
When to Specify Monel® 400
- Monel 400 vs. 316L stainless — Monel 400 dramatically outperforms 316L in seawater (especially flowing seawater) and HF service. 316L is preferred for oxidizing acids where Monel is rapidly attacked.
- Monel 400 vs. K-500 — K-500 is precipitation-hardened with about 3x the yield strength of 400 but is otherwise nearly identical in corrosion performance. Use K-500 when strength matters; use 400 when fabricability and cost are priorities.
- Monel 400 vs. 70/30 Cu-Ni (C71500) — Monel 400 has higher strength and broader chemical resistance. 70/30 Cu-Ni is preferred for high-velocity seawater service in heat exchanger tubing.
- Monel 400 vs. duplex stainless — Duplex is generally cheaper and stronger but doesn’t match Monel’s HF or pure seawater performance. Specify Monel for severe marine and HF service
Why Source 21?
- ISO 9001-certified quality system with full chemistry and mechanical traceability on every shipment
- Multi-million dollar national inventory across stainless, nickel alloys, copper, and brass
- Strong domestic and international mill relationships, including premium specialty mill partnerships
- In-house slitting, edging, leveling, and cut-to-length capabilities
- Contract programs, blanket orders, and vendor-managed inventory (VMI) for production accounts
- Responsive technical support for tight-tolerance and certification-driven work
Request a Quote
Contact Source 21 today for Monel 400 pricing, availability, and processing options. Our team responds quickly, asks the right questions, and gets you accurate quotes on real material — not vague placeholders.
Call 631-821-1101 or request a quote online to get started.