What is 718 Inconel?
Inconel 718 (or Alloy 718) is a high-strength, precipitation-hardenable, nickel-chromium superalloy known for its exceptional strength, corrosion resistance, and weldability, especially at extreme temperatures from cryogenic levels up to around 1300°F (700°C). It's a workhorse alloy used extensively in aerospace (jet engines, rockets), oil & gas, and nuclear industries for critical components like fasteners, turbines, and cryogenic storage.
What is the ASTM equivalent of Inconel 718?
The ASTM equivalent standards for Inconel 718 vary depending on the product form. Strip/plate uses ASTM B670, while bar stock uses ASTM B637. Both standards cover the same high-strength nickel alloy (UNS N07718), known for its high-temperature performance, and this alloy also conforms to aerospace material specifications (AMS), such as AMS 5596/5597.
Inconel 718 chemical composition
The makeup of Inconel 718 follows strict rules under standards like AMS 5662 and AMS 5663. This ensures it performs the same way every time.
| Element | Symbol | Weight Percentage (%) |
|---|---|---|
| Nickel | Ni | 50.0 - 55.0 |
| Chromium | Cr | 17.0 - 21.0 |
| Niobium (+ Tantalum) | Nb (+ Ta) | 4.75 - 5.50 |
| Molybdenum | Mo | 2.80 - 3.30 |
| Iron | Fe | Balance |
| Titanium | Ti | 0.65 - 1.15 |
| Aluminum | Al | 0.20 - 0.80 |
| Cobalt | Co | 1.0 max |
| Carbon | C | 0.08 max |
Inconel 718 material properties
| Property | Inconel 718 |
|---|---|
| Tensile Strength | 1370 MPa |
| Yield Strength | 1030 MPa |
| Elongation | 12-15% |
| Hardness (Rockwell) | B95-C36 |
Inconel 718 tensile strength
Inconel 718 plates, sheets, and coils typically have a tensile strength exceeding 1240 MPa (180 ksi) at room temperature, and maintain their strength even at high temperatures (up to approximately 700°C) due to their precipitation hardening (age hardening) characteristics. Strength varies significantly depending on the heat treatment (solution annealing + aging) and product form, with typical values ranging from approximately 965 MPa (140 ksi) in the annealed state to over 1379 MPa (200 ksi) after cold working or aging treatment.
What is the density of Inconel 718?
Inconel 718 has a typical density of 8.19 g/cm³ (0.296 lb/in³), making it a heavy, high-strength nickel alloy used in demanding aerospace and energy applications, with slight variations depending on processing, but consistently around 8.2 g/cm³
Inconel 718 Poisson ratio
Inconel 718 typically has a Poisson's ratio around 0.29 to 0.30 at room temperature, though it can vary slightly with processing (like 3D printing, where it might be 0.31-0.33) and decreases slightly at higher temperatures, with values like 0.284 or 0.29 being common figures in technical data, reflecting its elasticity as a superalloy.
heat treatment of Inconel® 718:
| Condition as supplied by AWI | Type | Temperature | Time | Cooling |
|---|---|---|---|---|
| No. 1 or Spring Temper | Anneal Age Harden Total Age |
980 °C (1800 °F) 720 °C (1330 °F) 620 °C (1150 °F) |
1hr 8hr 18hr |
Air Furnace Air |
| No. 1 or Spring Temper (for ISO 15156-3 / NACE MR 0175) |
Anneal Age Harden |
1010 °C (1850 °F) 790 °C (1455 °F) |
2hr 6hr |
Air Air |
| No. 1 Temper or Spring Temper | Age Harden Total Age |
720 °C (1330 °F) 620 °C (1150 °F) |
8hr 18hr |
Furnace Air |
For more information about Werkstoff 2.4668 rolled products, ASTM standards, Brinell hardness, and melting point, please contact us and refer to the specifications.
At GNEE, Inconel 718 is available in various forms to meet diverse industrial needs:
Plates and Sheets (cold rolled and hot rolled)
Bars and Rods (round, square, hexagonal)
Tubes (seamless and welded)
Wires and Strips (for springs, fasteners, electrical applications)
Forgings and Custom Parts (according to drawings or specifications)
Specifications: UNS NO7718, WNR 2.4668, AFNOR NC19FeNb, JIS NCF 718, GOST ХН75МБТЮ, EURONORM NiCr22Mo9Nb, OR ЭИ602, BS NA 21.
Temperature Range: -423°F to 1300°F.
Testing and Documentation: Mill Test Certificates, EN 10204 3.1, Chemical Reports, Mechanical Reports, Destructive Testing Reports, Non-Destructive Testing Reports, PMI Test Reports, Visual Inspection Reports, Third-Party Inspection Reports, NABL Certified Laboratory Reports.
Packaging: Wooden crates, bubble wrap, steel strapping, or packaged according to customer requirements.
