Alloy 718 (UNS N07718)
Precipitation-hardenable nickel–chromium superalloy — the workhorse grade for rotating and structural parts operating to ~700 °C.
- UNS
- N07718
- W.Nr / EN
- 2.4668
- Density
- 8.19 g/cm³
- Service range
- Cryogenic to ~700 °C
About Alloy 718
Alloy 718 is a precipitation-hardenable nickel–chromium alloy strengthened by niobium and molybdenum additions. Its defining advantage is a sluggish age-hardening response: the alloy can be welded and repair-welded in the aged condition without spontaneous hardening cracks, which is rare among high-strength superalloys.
The grade combines high tensile, fatigue and creep-rupture strength from cryogenic temperatures up to about 700 °C with good oxidation resistance to roughly 980 °C. That balance makes it the most widely specified wrought superalloy for turbine discs, shafts, fasteners, casings and high-pressure structural hardware. DMK Alloys supplies Alloy 718 as forged blanks, discs, bars and finish-contoured components, including complex shapes produced by powder metallurgy.
Alloy 718 chemical composition (weight %)
| Element | Limit / range |
|---|---|
| Ni (+Co) | 50.0 – 55.0 |
| Cr | 17.0 – 21.0 |
| Fe | Balance |
| Nb (+Ta) | 4.75 – 5.50 |
| Mo | 2.80 – 3.30 |
| Ti | 0.65 – 1.15 |
| Al | 0.20 – 0.80 |
| Co | ≤ 1.00 |
| C | ≤ 0.08 |
| Mn | ≤ 0.35 |
| Si | ≤ 0.35 |
| Cu | ≤ 0.30 |
| P | ≤ 0.015 |
| S | ≤ 0.015 |
| B | ≤ 0.006 |
Composition limits per the commonly referenced standards listed below. Order-specific limits may differ — confirm against the governing specification.
Alloy 718 mechanical properties (typical)
| Condition / form | Tensile, MPa | 0.2% Yield, MPa | Elongation, % |
|---|---|---|---|
| Bar, solution treated + aged, room temp. | 1240 – 1380 | 1030 – 1170 | 12 – 20 |
| Sheet, solution treated + aged, room temp. | ≥ 1240 | ≥ 1030 | ≥ 12 |
| Bar, solution treated + aged, 650 °C | ≈ 1000 | ≈ 860 | ≥ 12 |
Values are typical or specification-minimum levels for guidance only — not a guarantee of properties. Certified values are established by testing against the ordered specification.
Alloy 718 specifications & international equivalents
| System | Designation | Covers |
|---|---|---|
| UNS | N07718 | All product forms |
| AMS | AMS 5662 / 5663 / 5664 | Bars, forgings, rings |
| AMS | AMS 5596 / 5597 | Sheet, strip, plate |
| AMS | AMS 5832 | Welding wire |
| ASTM | ASTM B637 | Bars, forgings |
| ASTM | ASTM B670 | Plate, sheet, strip |
| W.Nr / EN | 2.4668 · NiCr19NbMo | European cross-reference |
| API | API 6A718 | Oil & gas wellhead components |
Cross-references are for guidance; the governing document is always the specification cited on your purchase order or drawing.
Alloy 718 physical properties
| Property | Typical value |
|---|---|
| Density | 8.19 g/cm³ |
| Melting range | 1260 – 1336 °C |
| Modulus of elasticity (family-typical) | ≈ 200 – 220 GPa |
| Indicative service range | Cryogenic to ~700 °C |
Forms we manufacture
- Forged discs and disc blanks
- Bars and billets
- Rings
- Near-net-shape PM components
- Machined blanks to drawing
Dimensional ranges and delivery conditions are confirmed per enquiry.
Where Alloy 718 earns its keep
Typically specified for:
- Gas-turbine discs
- Shafts
- Casings
- Fasteners
- Cryogenic hardware
- High-pressure components
Also consider
Alloy 625
UNS N06625 · W.Nr 2.4856AMS 5666 · AMS 5599
Solid-solution nickel–chromium–molybdenum–niobium alloy with outstanding corrosion resistance and strength without age hardening.
Alloy X-750
UNS N07750 · W.Nr 2.4669AMS 5667 / 5668 / 5670 / 5671 · AMS 5598
Age-hardenable nickel–chromium alloy for springs, fasteners and rotating hardware needing strength plus relaxation resistance.
Alloy 80A
UNS N07080 · W.Nr 2.4952AMS 5766 · ASTM B637
The classic age-hardenable 80/20 nickel–chromium superalloy for blading and high-temperature fasteners.
Request Alloy 718 to your specification
State the governing standard, form, dimensions, quantity and testing requirements — the export team responds with a manufacturer's quotation.