Monel K500 VS Inconel 718
Is Inconel 718 alloy non-magnetic?
Inconel 718 (UNS N07718, DIN 2.4375) is a widely used nickel-based alloy with a large number of alloying additives. As a nickel-based alloy, it is virtually non-magnetic.
What is the difference between Monel K500 and Inconel 718?
Monel K500 offers excellent corrosion resistance and mechanical properties in marine and chemical environments, while Inconel 718 offers excellent high temperature stability and oxidation resistance in aerospace and nuclear applications.
What is the maximum hardness of Inconel 718?
The hardness of Inconel 718 varies depending on heat treatment and processing conditions. In the solution annealed condition, its hardness is typically around 25-35 HRC (Rockwell C). After precipitation hardening, the hardness can be increased to around 36-45 HRC.
What is Inconel 718 alloy used for?
Inconel 718 alloy is commonly used in the aerospace industry. Engineers are constantly looking to improve the reliability and efficiency of engines, not to mention extend their service life. High-temperature alloys, especially 718 alloy, are widely selected for their balance between cost and performance.
Monel K500 and Inconel 718 Specifications
Monel K500 vs Inconel 718 ASTM Standards
| Shape | Monel K500 ASTM Standard | Inconel 718 ASTM Standard |
| Bars & Shapes | ASTM B865 | ASTM B637 |
| Sheet | - | ASTM B670 |
| Plate | - | ASTM B168 |
| Pipe | - | ASTM B444, ASTM B829 |
Monel K500 vs Inconel 718 Chemical Composition
| Element | Monel K500 Composition (%) | Inconel 718 Composition (%) |
| Nickel (Ni) | 63.0 – 70.0 | 50.0 – 55.0 |
| Copper (Cu) | 27.0 – 33.0 | ≤0.3 |
| Iron (Fe) | ≤2.0 | 17.0 – 21.0 |
| Chromium (Cr) | ≤0.5 | 17.0 – 21.0 |
| Molybdenum (Mo) | - | 2.8 – 3.3 |
| Niobium (Nb) | - | 4.75 – 5.50 |
| Aluminum (Al) | 2.3 – 3.2 | ≤0.2 |
| Titanium (Ti) | 0.35 – 0.85 | 0.65 – 1.15 |
| Cobalt (Co) | - | ≤1.0 |
| Manganese (Mn) | ≤1.5 | ≤0.35 |
| Silicon (Si) | ≤0.5 | ≤0.35 |
| Phosphorus (P) | ≤0.02 | ≤0.015 |
| Sulfur (S) | ≤0.01 | ≤0.015 |
Monel K500 vs Inconel 718 Corrosion Resistance
| Property | Monel K500 | Inconel 718 |
| Saltwater Resistance | Excellent, corrosion rate ~0.0005 in/yr (0.0127 mm/yr) | Good, corrosion rate ~0.002 in/yr (0.0508 mm/yr) |
| Acid Resistance | Moderate, best in reducing environments (sulfuric acid) | High, resistant to sulfuric and hydrochloric acids |
| Oxidation Resistance | Limited up to 980°F (530°C) | Excellent up to 1300°F (705°C), oxidation rate <0.001 in/yr |
Monel K500 vs Inconel 718 Physical Properties
| Property | Monel K500 | Inconel 718 |
| Density (g/cm³) | 8.44 | 8.19 |
| Melting Point (°C) | 1350 – 1380 | 1260 – 1340 |
| Electrical Resistivity (µΩ·m) | 0.47 | 1.29 |
Monel K500 vs Inconel 718 Mechanical Properties
| Property | Monel K500 | Inconel 718 |
| Tensile Strength (MPa) | 965 – 1100 | 1035 – 1375 |
| Yield Strength (MPa) | 690 | 725 |
| Elongation (%) | 20 | 30 |
| Hardness (Rockwell C) | 32 – 38 | 30 – 40 |
Monel K500 vs Inconel 718 Temperature Resistance
| Property | Monel K500 | Inconel 718 |
| Maximum Operating Temperature | 980°F (530°C) | 1300°F (705°C) |
| Temperature Stability | Stable up to 980°F, suitable for moderate environments | High stability up to 1300°F, resists deformation |
| Oxidation Resistance | Limited, effective up to 980°F in non-oxidizing environments | Excellent, stable in oxidizing environments up to 1300°F |
| Creep Resistance | Moderate, performs best under 980°F | High, maintains structure under sustained high temperatures |
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 |
Conclusion
In this comparison of Monel K500 vs. Inconel 718, each alloy offers unique advantages: Monel K500 is ideal for corrosion-resistant, moderate-temperature applications, while Inconel 718 excels in high-temperature, high-stress environments such as aerospace. Choosing the right alloy depends on your specific needs. Contact Gnee Steel today for a customized recommendation and explore our full range of high-performance alloys to find the product that best meets your needs!
