Monel 400 — nickel-copper alloy with outstanding resistance to hydrofluoric acid and seawater. For marine pumps, HF acid pickling equipment and chemical plant.
Standards
| Standard Body |
Designation |
Country |
| ASTM B164 |
Monel 400 bar (standard) |
USA |
| UNS |
N04400 |
USA |
| EN |
NiCu30Fe / 2.4360 |
EU |
| ASME |
SB-164 (pressure vessel use) |
USA |
| AMS |
AMS 4730 (bar) |
USA |
| Trade Name |
Monel 400 (Special Metals) / Nicorros 400 (ThyssenKrupp) |
Global |
| JUS |
Ni-Cu 30 legura; JUS C.B7.010 |
Yugoslavia |
Composition (wt.%)
| Element |
Symbol |
Min % |
Max % |
Typical % |
| Nickel |
Ni |
63.000 |
— |
66.500 |
| Copper |
Cu |
28.000 |
34.000 |
31.500 |
| Iron |
Fe |
— |
2.500 |
1.200 |
| Manganese |
Mn |
— |
2.000 |
1.000 |
| Carbon |
C |
— |
0.300 |
0.150 |
Physical
Melting Range
1300 – 1350
°C
Thermal Conductivity
21.8
W/mK
Thermal Expansion
13.9
×10⁻⁶/K
Machinability
| Rating |
35.0% (B1112=100%) |
| Turning HSS |
15.0 m/min |
| Turning Carbide |
75.0 m/min |
| Surface Finish |
Ra 0.8-3.2 um |
| Coolant |
High-pressure flood coolant mandatory |
Mechanical
| Condition |
Rm (MPa) | Re (MPa) | A (%) |
HB | HRC | KV (J) | E (GPa) |
| Annealed (+A) |
480 – 690 |
≥170 |
≥35 |
— |
— |
— |
179 |
| Cold Drawn H02 (H02) |
620 – 827 |
≥517 |
≥15 |
— |
— |
— |
179 |
Heat Treatment
| Process |
Temperature |
Medium |
Duration |
Hardness After |
| Annealing |
760 – 925°C |
Air or inert |
15-60 min |
Rm 480-690 MPa |
| Stress Relief |
275 – 345°C |
Air oven |
1-2 h |
Minimal |
Applications
Marine: Ship propeller shafts, seawater valve bodies, pump casings for seawater and brine service.
HF Acid Plant: HF acid alkylation unit piping, heat exchangers and vessel internals — primary HF application.
Chemical: Neutral and alkaline salt solutions, hydrofluoric acid, sulphuric acid and organic acids.
Food Processing: Cooking and processing vessels for acidic foods where iron contamination must be avoided.
Notes
HF Acid Resistance: Monel 400 is uniquely resistant to hydrofluoric acid (HF) at all concentrations and temperatures — HF dissolves most alloys. The standard material for HF alkylation units in petroleum refineries. No other common alloy can replace it for concentrated HF service.
Monel 400 vs Inconel 625 in seawater: Monel 400: good seawater resistance, lower cost, lower strength. Inconel 625: better pitting resistance (PRE=52 vs ~15), better for aggressive Cl. Use Monel 400 for general seawater; 625 for severe chloride pitting environments.