Inconel 625 is ideal for high-temperature, corrosive environments, while Inconel 718 is better suited for high-strength, high-stress applications—material selection should be based on specific service conditions.
Inconel alloys are widely used in extreme environments due to their excellent heat and corrosion resistance. Among them, Inconel 625 and Inconel 718 are two top choices. Here's a detailed comparison:
| Element |
Inconel 625 (%) |
Inconel 718 (%) |
| Nickel (Ni) |
≥58 |
50–55 |
| Chromium (Cr) |
20–23 |
17–21 |
| Molybdenum |
8–10 |
2.8–3.3 |
| Iron (Fe) |
≤5 |
Balance |
| Nb + Ta |
3.15–4.15 |
4.75–5.5 |
| Al, Ti |
Trace |
Present (0.2–1.15) |
Performance comparison of Inconel 625 and Inconel 718
| Property |
Inconel 625 |
Inconel 718 |
| Tensile Strength |
≥827 MPa |
≥1030 MPa |
| Yield Strength |
≥414 MPa |
≥720 MPa |
| Temp Range |
-253°C to 980°C |
-253°C to 700°C |
| Weldability |
Excellent |
Good |
| Corrosion Resistance |
Outstanding (seawater/chemical) |
Excellent (less corrosion focus) |
Applications
Inconel 625 tubing: Used in chemical plants, marine systems, flue gas ducts.
Inconel 718 tubing: Suitable for aerospace engines, gas turbines, and heavy structures.
Conclusion:
Choose Inconel 718 when high strength is critical. Choose Inconel 625 when corrosion and thermal resistance are priorities. Proper selection leads to long-term safety and performance.
