Inconel 718
An age-hardenable nickel-based superalloy
Typical values for the temper in the title
Inconel 718 is the most widely used superalloy. It contains 50–55% nickel, chromium, niobium, molybdenum and titanium, and is age hardened to about 1240–1380 MPa tensile. It keeps its strength up to about 650 °C.
Its special advantage: hardening is relatively slow, so it welds without post-weld strain-age cracking, unlike other superalloys. It is used for jet engine discs and parts, high-strength fasteners, missile parts and oil and gas tools. It is also a common metal printing material.
Mechanical and physical properties
| Property | Value | Note |
|---|---|---|
| Tensile strength Rm | 1240–1380 MPa | |
| Yield strength Rp0.2 | 1035–1170 MPa | |
| Elongation A | 12% | |
| Hardness | 330–400 HB | |
| Modulus of elasticity E | 200 GPa | |
| Density ρ | 8.22 g/cm³ | |
| Machinability | 20% | relative rating in the site database |
Chemical composition (wt %)
| Element | Range | Role |
|---|---|---|
| Ni nickel | 50.0–55.0 | |
| Cr chromium | 17.0–21.0 | oxidation resistance |
| Nb+Ta niobium | 4.75–5.50 | forms the strengthening particles |
| Mo molybdenum | 2.80–3.30 | strengthening |
| Ti titanium | 0.65–1.15 | strengthening |
| Al aluminum | about 0.2–0.8 | |
| Fe iron | balance |
Ranges per Alloy Wire and Special Metals data (UNS N07718).
Conditions and heat treatment
718 is hardened by solution treatment and double aging (usually at about 720 °C, then about 620 °C).
| Condition | Properties | When to choose it |
|---|---|---|
| Solution treated | relatively soft | machining and welding |
| Solution treated and double aged | Rm about 1240–1380 MPa (database value) | the finished part |
Applications
- Jet engine discs and parts
- High-strength fasteners
- Missile and space parts
- Oil and gas tools
- Metal-printed parts
Fabrication
Welding
Welds well for a superalloy, usually with ERNiFeCr-2 filler, and is aged after welding.
Machining
Nickel alloys work harden, stay strong when hot, and wear tools. Use low speed, a steady feed that does not "rub", sharp rigid tools and plenty of coolant.
Heat
Keeps its strength up to about 650 °C. Above that the strengthening particles change and strength drops.
Compared with similar materials
| Material | Rm / Rp0.2 | Welding | When it is the better choice |
|---|---|---|---|
| Inconel 625 | 827–1034 / 414–758 MPa | Excellent — ERNiCrMo-3 | not age hardened, more corrosion resistant · material page |
| Waspaloy | 1275 / 790 MPa | Complex | for higher heat · material page |
| Ti-6Al-4V (Grade 5) | 950–1100 / 880 MPa | Good — ERTi-5 | titanium, much lighter, for lower heat · material page |
| AM Inconel 718 | 1240-1350 / 1030-1100 MPa | Not applicable — as-built | 718 by printing (AM): parts with internal channels · material page |
Common mistakes
Machining in the aged condition
The material is very hard. Machine mainly solution treated.
Using 718 above about 650 °C
Strength drops. For higher heat, alloys such as Waspaloy.
Welding with non-matching filler
The weld will not reach the base-metal strength.
Equivalents, standards and supply
| EN | 2.4668 |
|---|---|
| DIN | NiCr19Fe19Nb5Mo3 |
| JIS | NCF718 |
| Standards | ASTM B637 / AMS 5596 / EN 10269 |
| Forms | plate · rod · forging · pipe |
| Producers | Special Metals · ATI · VDM · Allegheny · Valbruna |
Learn more
Values are typical and for comparison only. For design, rely on the standard and the mill certificate. Sources: ASTM (B127, B164, B168, B443, B575, B619 and others), Special Metals and Haynes data sheets, and the METAL HUB materials database. Inconel and Monel are trademarks of Special Metals, and Hastelloy of Haynes International.
Updated: October 31, 2026