Monel K500 vs Inconel 718 – These are both high-performance nickel alloys, but they differ significantly in composition, mechanical strength, corrosion resistance, and typical applications. Here's a detailed comparison:
🔹 Chemical Composition
| Element | Monel K500 (UNS N05500) | Inconel 718 (UNS N07718) |
|---|---|---|
| Nickel (Ni) | 63% min | 50–55% |
| Copper (Cu) | 27–33% | ≤ 0.30% |
| Iron (Fe) | ≤ 2.0% | Balance |
| Chromium (Cr) | ≤ 0.25% | 17–21% |
| Molybdenum (Mo) | - | 2.8–3.3% |
| Al + Ti (Aging elements) | 2.3–3.15% combined | 0.65% Ti, 0.9% Al |
| Niobium (Nb) | - | 4.75–5.5% |
🔹 Mechanical Properties (Age-Hardened)
| Property | Monel K500 | Inconel 718 |
|---|---|---|
| Tensile Strength | Up to 160 ksi (1100 MPa) | Up to 200 ksi (1375 MPa) |
| Yield Strength | Up to 110 ksi (758 MPa) | Up to 170 ksi (1170 MPa) |
| Hardness | Up to 45 HRC | Up to 44 HRC |
| Max Service Temp. | ~600°C (1110°F) | ~700°C (1300°F) |
🔹 Corrosion Resistance
| Environment | Monel K500 | Inconel 718 |
|---|---|---|
| Seawater | Excellent | Good |
| Acids (HCl, H2SO4) | Good (esp. reducing acids) | Excellent (esp. oxidizing) |
| Oxidation Resistance | Moderate | Excellent |
🔹 Applications
| Industry | Monel K500 | Inconel 718 |
|---|---|---|
| Marine | Propeller shafts, pump shafts | Less common |
| Oil & Gas | Drill collars, valve trim, downhole tools | High-pressure tubing, fasteners |
| Aerospace | Springs, fasteners | Turbine disks, jet engine parts |
| Chemical Processing | Pumps, valves | Superheater tubes, pressure vessels |
🔹 Summary Comparison
| Criteria | Monel K500 | Inconel 718 |
|---|---|---|
| Strength (aged) | High | Very High |
| Corrosion Resistance | Best in seawater | Superior in high-temp and acid environments |
| Cost | Lower | Higher |
| Machinability | Moderate | Difficult (work hardens quickly) |
| Weldability | Fair (requires care) | Excellent (especially with proper filler) |
🔧 SSM Can Supply:
Monel K500: Rods, flanges, fittings, fasteners
Inconel 718: Plates, bars, rings, custom forgings
