Alloy 718, UNS N07718, is the most widely used nickel superalloy in the world. Niobium and molybdenum strengthening through the gamma double prime phase gives it very high strength to roughly 1300F, and because that phase precipitates slowly the alloy can be welded and then aged without the strain age cracking that plagues faster hardening superalloys.
That weldability, combined with excellent fatigue, creep and rupture strength and good cryogenic behaviour, makes 718 the default engine alloy: discs, casings, shafts, fasteners, seals, springs and ducting across turbine engines, plus extensive use in oil and gas and rocketry.
We stock 718 as bar, billet, plate, sheet, tube, wire and forgings, supplied annealed, solution treated, or solution treated and aged to AMS 5662, AMS 5663, AMS 5596, AMS 5597 and related specifications.
Sizes and stock
- Round bar: up to 12" DIA
- Foil: from .0005" THK
- Sheet / plate: up to 5" THK
- Tube: various sizes
- Forgings and flat bar: by request
Processing capabilities
- Billet conversion and open die, closed die and ring forging
- Solution treat, age and anneal to the applicable spec
- Saw cutting, trepanning, gun drilling and CNC machining
- Ultrasonic, penetrant dye, micrography and physical testing
Cold reduced material per AMS 5962 available up to 2" DIA.
Specifications
Material is released to the applicable specification with mill test reports and, on request, independent lab verification.
Why engineers specify Inconel 718
- Very high strength to about 1300F
- Weldable and age hardenable without strain age cracking
- Excellent fatigue, creep and stress rupture properties
- Good cryogenic toughness and broad specification coverage
Nominal chemistry
Percent by weight, nominal composition per the governing specification. The mill test report for your heat is the controlling document.
Typical mechanical properties
| Condition | Tensile strength | Yield strength | Elongation | Hardness |
|---|---|---|---|---|
| Solution annealed | ~130 ksi | ~70 ksi | ~45% | - |
| Solution treated and aged (AMS 5662) | 180 ksi min | 150 ksi min | 12% min | 331 HBW min |
| STA at 1200F | ~155 ksi | ~135 ksi | ~15% | - |
Typical published values for reference only, not for design. Properties vary with section size, product form and processing. Order to the specification and condition your drawing requires.
Heat treatment and conditions
- 01Solution treat at 1750F to 1800F for AMS 5662 or 1900F to 1950F for AMS 5663 coarse grain practice
- 02Age 1325F for 8 hours, furnace cool to 1150F, hold to a total aging time of roughly 18 hours, air cool
- 03Weld in the solution treated condition and age afterward
If our stock is not already in the condition you need, we can quote the material with the heat treatment performed before it ships.
Typical applications
- Turbine discs, spacers and seals
- Engine casings and ducting
- High temperature fasteners and springs
- Rocket engine components
- Downhole tools and subsea hardware
Fabrication notes
Machining
Nickel and cobalt superalloys work harden aggressively. Use rigid setups, sharp tooling, slow speeds, positive feed that stays under the hardened skin, and flood coolant. Age hardened material machines far more slowly than solution treated material, so rough before aging wherever the print allows.
Welding
Most solid solution grades weld readily with matching filler. Age hardenable grades such as 718 and Waspaloy are welded in the solution treated condition and aged afterward to control strain age cracking.
Forming
Hot working ranges are narrow and forces are high. Cold form in the annealed condition with intermediate anneals, and stress relieve before final heat treatment.
Inconel 718 compared with similar grades
Alloy 625
Solid solution strengthened, far more corrosion resistant, much lower strength.
Waspaloy
Higher temperature capability to around 1600F, harder to weld.
A286
Iron based, lower cost and lower temperature capability, common in fasteners.
Designations and cross reference
- Material family
- Nickel & Cobalt Alloys
- UNS number
- N07718
- Werkstoff (W.Nr)
- 2.4668
- EN designation
- NiCr19Fe19Nb5Mo3
- ASTM
- B637 (bar/forgings), B670 (sheet/plate)
- AMS by form
- 5662/5663/5664 (bar/forgings), 5596/5597 (sheet/plate)
Working from an obsolete, foreign or superseded designation? Send it over and we will cross reference it to a current grade and specification.
Quality, testing and traceability
Supplied with mill test reports and heat traceability, with ultrasonic inspection, penetrant dye, micrography, grain size, stress rupture and mechanical testing available on request.
We are AS9100D and ISO 9001:2015 registered. If our stock does not already carry the inspection your specification requires, we can quote the material with that work performed. More on our quality system
Available forms
Inconel 718 frequently asked questions
What is Inconel 718?
Alloy 718, UNS N07718, is the most widely used nickel superalloy in the world. Niobium and molybdenum strengthening through the gamma double prime phase gives it very high strength to roughly 1300F, and because that phase precipitates slowly the alloy can be welded and then aged without the strain age cracking that plagues faster hardening superalloys.
What forms is Inconel 718 available in?
We supply Inconel 718 in bar, foil, sheet, plate, tube, forging. Custom sizes are converted from billet, and we can provide saw cut, waterjet or near net blanks so material arrives closer to your finished part.
What is the UNS or equivalent designation for Inconel 718?
Inconel 718 is designated UNS N07718, Werkstoff 2.4668, EN NiCr19Fe19Nb5Mo3. If your drawing calls out an obsolete or foreign designation we can cross reference it and confirm the equivalent before you order.
What specifications can Inconel 718 be supplied to?
Commonly ordered specifications include AMS 5962, AMS 5589, AMS 5590, AMS 5596, AMS 5662, B50TF14. Material is released to the specification and condition on your purchase order, with mill test reports supplied as standard.
What conditions can Inconel 718 be ordered in?
We can supply Solution annealed, Solution treated and aged (AMS 5662), STA at 1200F. If our stock is not already in the condition you need, we can quote it with the heat treatment performed before shipment.
Can you cut Inconel 718 to size?
Yes. Saw cutting, waterjet, laser and shearing are available, along with trepanning, gun drilling, lathe turning and CNC machining, so you can order blanks or rough machined pieces rather than full lengths.
Do you provide test reports and additional testing on Inconel 718?
Every order ships with mill test reports and heat traceability. If your print calls for ultrasonic inspection, penetrant dye, magnetic particle, chemical assay, micrography, hardness or mechanical testing and our stock does not already carry it, we can quote the material with that work performed.
Can Inconel 718 be supplied to DFARS domestic melt requirements?
Tell us at quote stage if the order is DFARS or domestic melt restricted and we will confirm availability against that requirement before you commit.
What do you need to quote Inconel 718?
Grade, form, dimensions, quantity, specification and condition, plus any testing or certification requirements and the date you need it. Send a drawing if you have one. Quotes are typically ready within 24 hours.
How does Inconel 718 compare with Alloy 625?
Solid solution strengthened, far more corrosion resistant, much lower strength.