Inconel 718 bars details
Inconel 718 bar (UNS N07718/GH4169) is a precipitation-hardening nickel-chromium-iron-based superalloy bar with ultra-high strength and excellent corrosion resistance in the range of -253°C to 700°C. This material is widely used in critical structural components in aerospace (engine turbine disks/blades), energy (nuclear power/gas turbine components), and chemical equipment, making it a reliable material choice for extreme high-temperature, high-pressure, and corrosive environments.
Inconel 718 bars (UNS N07718 / GH4169) are precipitation-hardening nickel-chromium-iron-based superalloy bars, renowned for their high strength, excellent corrosion resistance, and good weldability over a wide temperature range of -253°C to 700°C. These bars are widely used in the manufacture of structural components for extreme environments such as aerospace (e.g., engine turbine disks, blades), energy (e.g., nuclear reactor components), and chemical (e.g., reactors, heat exchangers).
Inconel 718 bars details
High-Temperature Strength: Maintains high strength even at 650℃, exhibiting excellent creep and fatigue resistance, making it the preferred material for manufacturing hot-end components such as turbine disks and blades for aero-engines.
Corrosion Resistance: Contains high levels of chromium and molybdenum, effectively resisting corrosion from oxidizing media, seawater, and acidic gases (such as H₂S and CO₂), making it suitable for petrochemical and marine engineering applications.
Processing Performance: Compared to other nickel-based superalloys, it exhibits better weldability, is less prone to cracking after welding, and possesses good cold and hot working properties.
| Elements | Ni | Cr | Fe | Nb | Mo | Ti | Al | C | Mn | Si | S | P |
| Standard | 50-55 | 17-21 | Balance | 4.75-5.50 | 2.8-3.3 | 0.65-1.15 | 0.28-0.8 | ≤0.08 | ≤0.35 | ≤0.35 | ≤0.015 | ≤0.015 |
3. Mechanical Properties
Tensile Strength: ≥1100 MPa
Yield Strength: ≥965 MPa
Elongation: ≥12%
Hardness: HRC ≥38
4. Heat Treatment Process
Solution Treatment: Hold at 980-1020℃ for 1-2 hours, then water quench or air cool.
Double Aging: Hold at 720℃ for 8 hours, then furnace cool to 620℃ and hold for 8 hours, followed by air cooling.
5. Application Areas
Aerospace: Jet engine turbine disks, compressor blades, combustion chamber liners.
Energy: Nuclear reactor control rod drive mechanisms, gas turbine blades.
Petrochemicals: Downhole tools, high-pressure pump casings, chemical reactors.
Marine Engineering: Seawater heat exchangers, underwater equipment fasteners.
6. Machining and Welding
Hot Working: Suitable temperature 1120-900℃, final forging temperature not lower than 960℃.
Cold working: Should be performed after solution treatment. Work hardening rate is high, so deformation must be controlled.
Welding: Tungsten inert gas welding (GTAW/TIG) is recommended. ERNiFeCr-2 welding wire is recommended. Post-weld aging treatment is required.
7. Standards and Grades
American Standards: ASTM B637 (plate), AMS 5662
Chinese Grade: GH4169
German Grade: W.Nr.2.4668
8. Physical Properties
Density: 8.19-8.24 g/cm³
Melting Point: 1260-1340℃
Coefficient of Thermal Expansion: 13.0 μm/m·℃ (20-100℃)
9. Microstructure
Matrix: Austenite (γ phase)
Strengthening Phases: γ″ phase (Ni₃Nb, main strengthening phase), γ′ phase (Ni₃(Al,Ti), auxiliary strengthening phase)
Grain Boundary Phase: δ phase (Ni₃Nb, controls grain growth)
10. Precautions
Work Hardening: Inconel Inconel 718 exhibits a strong tendency for work hardening, requiring low cutting speeds (20-30 m/min) and specialized cutting tools during machining.
Surface Cleaning: Thorough surface cleaning is essential before heating to prevent impurities such as sulfur and phosphorus from causing material embrittlement.
Aging Control: Excessively high aging temperatures or prolonged aging times can lead to excessive growth of the γ″ phase, reducing strength.
Inconel 718 bars, with their superior overall performance, have become an indispensable key material in aerospace, energy, and chemical industries.
In addition, Inconel 718 is used in the manufacture of fasteners such as bolts, and is widely used in aerospace, petrochemical, energy, marine engineering, and medical devices.
In summary, Inconel 718, with its excellent high-temperature strength, corrosion resistance, fatigue resistance, and good machinability, has demonstrated an irreplaceable role in many key areas. As materials science continues to advance, its application areas will continue to expand.
