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Alloy 718 Technical Overview
Inconel 718 (UNS N07718) is a high-strength, corrosion-resistant nickel-chromium material used at temperatures from -423° to 1300°F. The age-hardenable alloy can be readily fabricated, even into complex parts. Its welding characteristics, especially its resistance to post-weld cracking, are outstanding. The ease and economy with which Alloy 718 can be fabricated, combined with good tensile, fatigue, creep, and rupture strength, have resulted in its use in a wide range of applications. Examples of these are components for liquid-fueled rockets, rings, casings, and various formed sheet metal parts for aircraft and land-based gas turbine engines, and cryogenic tankage. Steel Emporium offers high-precision Inconel 718 pipes and tubes with full quality assurance.
Key Material Advantages
High Tensile Strength
Precipitation hardening provides extreme mechanical strength and toughness.
Excellent Weldability
Unlike many superalloys, it is resistant to strain-age cracking during welding.
Creep Resistance
Maintains integrity under high stress at temperatures up to 1300°F (700°C).
| Grade | Ni | Cr | Fe | Nb+Ta | Mo | Ti | Al | C |
|---|---|---|---|---|---|---|---|---|
| Inconel 718 | 50.0 - 55.0 | 17.0 - 21.0 | Balance | 4.75 - 5.50 | 2.80 - 3.30 | 0.65 - 1.15 | 0.20 - 0.80 | 0.08 max |
| Property | Metric Value | Imperial Value |
|---|---|---|
| Tensile Strength (min) | 1240 MPa | 180,000 psi |
| Yield Strength (0.2% offset) | 1035 MPa | 150,000 psi |
| Elongation (% in 50mm) | 12% min | 12% min |
| Hardness (Brinell) | 331 HB min | 36 HRC min |
| Property | Value |
|---|---|
| Density | 8.19 g/cm³ (0.296 lb/in³) |
| Melting Range | 1260 - 1336 °C (2300 - 2437 °F) |
| Specific Heat | 435 J/kg·°C (0.104 Btu/lb·°F) |
| Thermal Conductivity (20°C) | 11.4 W/m·°C |
| Standard | UNS Number | Werkstoff No. | AFNOR | Common Name |
|---|---|---|---|---|
| Alloy 718 | N07718 | 2.4668 | NC19FeNb | Inconel 718 |
| Nominal Size (NB) | OD (mm) | SCH 10 | SCH 40 | SCH 80 |
|---|---|---|---|---|
| 1/2" | 21.34 | 1.30 | 1.66 | 2.16 |
| 1" | 33.40 | 2.14 | 3.31 | 4.33 |
| 2" | 60.33 | 4.01 | 5.56 | 7.64 |
| 3" | 88.90 | 6.85 | 11.55 | 15.61 |
| 4" | 114.30 | 11.26 | 16.42 | 22.79 |
Industrial Applications
Jet Engines
Compressor blades, discs, and shafts.
Space Hardware
Liquid-fueled rocket engine components.
Downhole Tools
High-strength bolts and oil field mandrels.
Nuclear Industry
Fuel element spacers and spring components.
Cryogenics
Cryogenic storage tanks and piping.
Fasteners
High-temperature bolts and hardware.