1. What is the chemical composition of Inconel 718 (UNS N07718)?
Answer:
Nickel (Ni): 50–55%
Chromium (Cr): 17–21%
Iron (Fe): 17% max
Niobium (Nb) + Tantalum (Ta): 4.75–5.5%
Molybdenum (Mo): 2.8–3.3%
Cobalt (Co): 1% max
Titanium (Ti): 0.65–1.15%
Aluminum (Al): 0.2–0.8%
Carbon (C): 0.08% max
This composition provides excellent creep and oxidation resistance at high temperatures, making it suitable for aerospace and industrial applications.
2. What are the mechanical properties of Inconel 718 plate?
Answer (typical for solution-treated and aged condition):
Tensile Strength: 1240–1380 MPa
Yield Strength: 1030–1100 MPa
Elongation: 12–20%
Hardness (Rockwell B/C): 32 HRC max
Exceptional creep resistance up to 650–700°C and fatigue strength, suitable for high-stress, high-temperature applications.
3. What does "creep resistant" mean for Inconel 718?
Answer:
Creep resistance refers to the material's ability to resist deformation under constant stress at high temperatures over long periods.
Inconel 718 achieves this through precipitation hardening via Nb and Ti additions.
This makes it ideal for turbine disks, high-temperature valves, and reactor components.
4. How does Inconel 718 compare to Inconel 600 and Incoloy 825?
Answer:
Inconel 718: Superior high-temperature strength and creep resistance.
Inconel 600: Excellent corrosion and oxidation resistance, but lower high-temperature strength.
Incoloy 825: Excellent resistance to acid and chloride corrosion, suitable for chemical environments.
Selection depends on operating temperature, corrosion type, and mechanical load.
5. What are the typical applications for Inconel 718 creep-resistant plates?
Answer:
Aerospace components like turbine discs, compressor blades, and fasteners
High-temperature industrial furnace and heat-treatment equipment
Chemical and petrochemical reactor components
Marine engineering where high-stress and high-temperature corrosion resistance is required
