Monel 400 VS Inconel 718 Alloy
Why is Inconel 718 difficult to machine?
The excellent performance of Inconel 718 nickel-based superalloy at high temperatures makes it widely used in the aviation, marine and automotive industries. However, Inconel 718 has poor thermal conductivity and rapid strain hardening, resulting in poor machinability and machined surface integrity.
What is the difference between Monel 400 and Inconel 718?
In terms of composition, Monel 400 can also withstand high temperatures and pressures, making it suitable for the shipbuilding and chemical industries. Inconel 718 is a nickel-chromium alloy with a nickel content of up to 55%, a chromium content of up to 21%, and small amounts of iron, niobium, and molybdenum.
Will Inconel 718 rust?
Although Inconel 718 has good corrosion resistance in general seawater environments, corrosion may occur in certain extreme marine conditions, such as high salinity, high temperatures, and elevated chloride ion concentrations.
Can Inconel 718 alloy be welded?
Inconel 718 alloy has excellent weldability in both the age-hardened and annealed conditions. Although the alloy has a high resistance to strain-age cracking, some weldability issues exist, such as microcracking and solidification cracking.
Monel 400 and Inconel 718 Specifications
Inconel 718 Vs Monel 400 Alloy Chemical Composition:
| Element | Inconel 718 | Monel 400 |
|---|---|---|
| Ni | 50.0% – 55.0% | 63.0% min |
| Cr | 17.0% – 21.0% | None |
| Fe | Balance (primary) | 2.5% max |
| Mo | 2.8% – 3.3% | None |
| Nb | 4.75% – 5.50% | None |
| Cu | None | 28.0% – 34.0% |
| Co | 1.0% max | None |
| Mn | 0.35% max | 2.0% max |
| Si | 0.35% max | 0.5% max |
| C | 0.08% max | 0.3% max |
| S | (Not specified) | 0.024% max |
| Al | 0.2% – 0.8% | None |
| Ti | 0.65% – 1.15% | None |
Inconel 718 Vs Monel 400 Alloy Mechanical Properties:
| Property | Inconel 718 | Monel 400 |
|---|---|---|
| Tensile Strength | 965 - 1035 MPa | 480 - 620 MPa |
| Yield Strength | 550 - 725 MPa | 170 - 345 MPa |
| Elongation | 12% - 20% | 35% - 50% |
| Brinell Hardness | 300 - 370 HB | 120 - 150 HB |
| Density | 8.19 g/cm³ | 8.80 g/cm³ |
| Melting Point | 1260°C - 1336°C | 1300°C - 1350°C |
Inconel 718 Vs Monel 400 Alloy Physical Properties:
| Property | Inconel 718 | Monel 400 |
|---|---|---|
| Density | 8.19 g/cm³ | 8.80 g/cm³ |
| Thermal Conductivity | 11.4 W/m·K | 21.8 W/m·K |
| Specific Heat | 435 J/kg·K | 410 J/kg·K |
| Melting Point | 1260°C – 1336°C | 1300°C – 1350°C |
| Electrical Resistivity | 1.25 µΩ·m | 0.49 µΩ·m |
| Magnetic Properties | Non-magnetic | Slightly magnetic |
Conclusion:
In summary, both Monel 400 and Inconel 718 are excellent nickel-based alloys with excellent corrosion resistance and mechanical properties. The choice of alloy depends on the specific application and the required properties, such as strength, high temperature and pressure resistance, and corrosion and erosion resistance. Monel 400 is more suitable for marine and chemical applications, while Inconel 718 is more suitable for the aerospace and gas turbine industries. The cost of each alloy depends on the specific application and supplier, but generally, Monel 400 is less expensive than Inconel 718. By understanding the differences between these two alloys, engineers and manufacturers can choose the most appropriate material for their specific needs.
