1. Composition & Strengthening Mechanism
| Property | Monel 400 | Monel K500 |
|---|---|---|
| Base Composition | 67% Ni, 30% Cu, 1% Fe, 1% Mn | 63% Ni, 30% Cu, 2% Al, 0.5% Ti |
| Key Additive | None (solid solution strengthening) | Aluminum + Titanium (age-hardening) |
2. Mechanical Properties
| Parameter | Monel 400 | Monel K500 (Aged) |
|---|---|---|
| Tensile Strength | 550 MPa (80 ksi) | 1100 MPa (160 ksi) |
| Yield Strength | 240 MPa (35 ksi) | 760 MPa (110 ksi) |
| Hardness | 150 HBW | 250 HBW |
| Elongation | 35% | 20% |
3. Corrosion Resistance
Shared Strengths:
✓ Excellent resistance to seawater, sulfuric/hydrochloric acids
✓ Low corrosion rates in marine/chemical environments
K500 Advantage:
▪ Superior stress-corrosion cracking resistance due to aging treatment
4. Typical Applications
| Monel 400 | Monel K500 |
|---|---|
| • Heat exchanger tubes | • Offshore drill collars |
| • Marine piping systems | • Pump shafts in sour gas wells |
| • Chemical processing vessels | • High-strength fasteners |
| • Valve components | • Aerospace bearings |
5. Cost & Fabrication
K500: ~30-50% more expensive due to aging process; requires post-weld heat treatment.
400: Easier to weld/cold-work; lower total cost for non-critical applications.
Choose Monel 400 for general corrosion resistance; opt for K500 when high strength + corrosion resistance are both critical (e.g., subsea valves). Always verify compatibility with specific service environments.
