Nickel Alloy Inconel 718 · precip hard
Nickel Alloy Inconel 718 Direct Aged
Properties of the Direct Aged condition, compared with the other Inconel 718 tempers.
Fine-grain, highest-strength route for discs and fasteners where creep at ≤650 °C and tensile strength dominate.
What is Inconel 718 Direct Aged?
Inconel 718 Direct Aged is Inconel 718 in the Direct Aged condition — fine-grain, highest-strength route for discs and fasteners where creep at ≤650 °C and tensile strength dominate. Inconel 718 Direct Aged has a yield strength of 1,250 MPa (181 ksi) and a tensile strength of 1,450 MPa (210 ksi) — stronger than 100% of nickel alloy grades. Elongation at break is 15% and the elastic modulus is 200 GPa (29 Msi). Inconel 718 Direct Aged has a density of 8.19 g/cm³ (0.296 lb/in³), lighter than 67% of nickel alloy grades. It melts at 1,260°C (2,300 °F). Solution Annealed is the default condition FabDigit quotes; Direct Aged is available on request or by drawing note.
Advantages
- High strength — 1,250 MPa (181 ksi), better than 100% of nickel alloy grades
- Polishes to a fine finish — 80/100, better than 97% of nickel alloy grades
Limitations
- Difficult to machine — 9/100, worse than 95% of nickel alloy grades
- High embodied carbon — 16 kg CO₂/kg, worse than 93% of nickel alloy grades
- Limited ductility — 15%, worse than 82% of nickel alloy grades
- Low fracture toughness — 85 MPa·√m (77.4 ksi·√in), worse than 76% of nickel alloy grades
Inconel 718 Direct Aged properties
Typical room-temperature values for Inconel 718 Direct Aged — 9 properties are specific to this condition; the rest are grade-level values shared by every Inconel 718 temper. Each bar shows where the value sits among the nickel alloy grades in FabDigit's library — further right is higher.
Physical3
Inconel 718 Direct Aged has a density of 8.19 g/cm³ (0.296 lb/in³), lighter than 67% of nickel alloy grades. It melts at 1,260°C (2,300 °F).
Mechanical15
Inconel 718 Direct Aged has a yield strength of 1,250 MPa (181 ksi) and a tensile strength of 1,450 MPa (210 ksi) — stronger than 100% of nickel alloy grades. Elongation at break is 15% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
Inconel 718 Direct Aged is rated for continuous service to 650°C (1,202 °F). It conducts heat at 11.4 W/m·K (6.59 BTU/hr·ft·°F), better than 51% of nickel alloy grades. Thermal expansion is 13 µm/m·K (7.22 µin/in·°F).
Electrical3
Inconel 718 Direct Aged conducts electricity at 1.4 % IACS, worse than 66% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (78/100), better than 50% of nickel alloy grades.
Sustainability4
Producing a kilogram of Inconel 718 Direct Aged takes about 250 MJ of energy and emits 16 kg of CO₂ — more than 97% of nickel alloy grades. Typical recycled content is 35%.
Manufacturability8
Inconel 718 Direct Aged's machinability is not recommended (9/100, worse than 95% of nickel alloy grades); weldability very good (70/100); formability good (55/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other Inconel 718 tempers and conditions
Inconel 718 is also supplied in 10 other conditions. The full side-by-side table is on the Inconel 718 overview.
- Solution AnnealedDefaultStandard stocked condition for forming, machining and welding before customer-performed aging.550 MPa yield · 200 HB
- Direct AgedFine-grain, highest-strength route for discs and fasteners where creep at ≤650 °C and tensile strength dominate.1,250 MPa yield · 45 HRC
- AgedFull-strength service condition for turbine discs, shafts, fasteners and downhole tooling to 650 °C.1,170 MPa yield · 42 HRC
- As CastFor complex cast housings, casings and manifolds where wrought properties are not required.800 MPa yield · 36 HRC
- As PrintedReference state for AM prints straight off the plate; anisotropic with high residual stress, normally stress relieved + HIP + aged before service.700 MPa yield · 30 HRC
- HIPPick for cast or additively built 718 that must be pore-free and fatigue-critical; normally followed by aging.620 MPa yield · 210 HB
- As FabricatedMill/as-fabricated UNS N07718 supplied without final solution + precipitation treatment; moderate strength, high ductility, readily formed and welded before aging.560 MPa yield · 25 HRC
- AnnealedSoftest wrought condition, chosen for tube bending, deep drawing and welded fabrication.460 MPa yield · 180 HB
Working with Inconel 718 Direct Aged
Is Inconel 718 easy to machine?
Machine in the solution-annealed state where possible; rigid setups, low speed (20–35 m/min carbide, 150–250 m/min ceramic), heavy positive feed, sharp tools and flood coolant to beat work hardening and notch wear.
Can Inconel 718 be welded?
Very good fusion weldability by GTAW/EBW/LBW with ERNiFeCr-2 (718) filler in the annealed condition; keep heat input low, avoid restrained thick sections, and post-weld solution treat + age to restore full strength.
Can Inconel 718 be formed, bent or molded?
Hot work at 1010–1120 °C; cold form only from annealed stock with high tooling forces and intermediate anneals — springback and tool wear are severe.
What surface finishes work on Inconel 718?
Not anodizable; use pickling/passivation, electropolishing, abrasive blasting or shot peening for fatigue, plus diffusion or PVD coatings for high-temperature wear.
Inconel 718 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Niplus Co if reported | 50 – 55 | 53 |
| Cr | 17 – 21 | 19 |
| NbNb + Ta | 4.75 – 5.5 | 5.13 |
| Mo | 2.8 – 3.3 | 3.05 |
| Ti | 0.65 – 1.15 | 0.9 |
| Al | 0.2 – 0.8 | 0.5 |
| Co | ≤ 1 | 0.3 |
| C | ≤ 0.08 | 0.04 |
| Mn | ≤ 0.35 | 0.1 |
| Si | ≤ 0.35 | 0.1 |
| Cu | ≤ 0.3 | 0.05 |
| B | ≤ 0.01 | 0 |
| P | ≤ 0.02 | — |
| S | ≤ 0.02 | — |
| Tamax, when specified separately | ≤ 0.05 | — |
| Febalance, typically 17–20 % | balance | — |
Inconel 718 Direct Aged — frequently asked
What is Inconel 718 Direct Aged used for?
Inconel 718 Direct Aged is typically used for gas turbine disks and blades, high-temperature fasteners and studs, turbine casings and seal rings, rocket engine injectors and manifolds, downhole drilling and completion tooling and cryogenic valve stems and springs. In short: workhorse aerospace superalloy.
What is the yield strength of Inconel 718 Direct Aged?
Inconel 718 Direct Aged has a typical yield strength of 1,250 MPa (181 ksi) and a tensile strength of 1,450 MPa (210 ksi) — stronger than 100% of nickel alloy grades. Strength varies by condition: see the 11 listed tempers.
Is Inconel 718 Direct Aged easy to machine?
Not especially — machinability is rated not recommended (9/100, worse than 95% of nickel alloy grades). Machine in the solution-annealed state where possible; rigid setups, low speed (20–35 m/min carbide, 150–250 m/min ceramic), heavy positive feed, sharp tools and flood coolant to beat work hardening and notch wear.
Can Inconel 718 Direct Aged be welded?
Yes — weldability is rated very good (70/100). Very good fusion weldability by GTAW/EBW/LBW with ERNiFeCr-2 (718) filler in the annealed condition; keep heat input low, avoid restrained thick sections, and post-weld solution treat + age to restore full strength.
What surface finishes work on Inconel 718 Direct Aged?
Not anodizable; use pickling/passivation, electropolishing, abrasive blasting or shot peening for fatigue, plus diffusion or PVD coatings for high-temperature wear.
Can Inconel 718 Direct Aged be formed, bent or molded?
Hot work at 1010–1120 °C; cold form only from annealed stock with high tooling forces and intermediate anneals — springback and tool wear are severe.
What is the maximum service temperature of Inconel 718 Direct Aged?
Inconel 718 Direct Aged is rated for continuous use to about 650°C (1,202 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Inconel 718 Solution Annealed and Inconel 718 Aged?
Solution Annealed is the default condition — standard stocked condition for forming, machining and welding before customer-performed aging. Aged: full-strength service condition for turbine discs, shafts, fasteners and downhole tooling to 650 °C. Yield strength is 550 MPa in Solution Annealed versus 1,170 MPa in Aged.
Can FabDigit make parts in Inconel 718 Direct Aged?
Yes — Inconel 718 Direct Aged is available for CNC machining, sheet metal and 3D printing with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- INCONEL alloy 718 technical bulletin — Special Metals Corporation (2007)
- AMS 5662 / AMS 5663 — Nickel Alloy Bars, Forgings and Rings, 718 — SAE International (2020)
- ASTM B637 — Precipitation-Hardening Nickel Alloy Bars, Forgings and Forging Stock for High-Temperature Service — ASTM (2018)
- ASTM B670 / AMS 5596 — Alloy 718 Plate, Sheet and Strip — ASTM / SAE (2019)
- AMS 5383 — Nickel Alloy Castings, Investment, 718 — SAE International (2018)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- MMPDS-17 — Metallic Materials Properties Development and Standardization — Battelle/FAA (2022)
- EOS NickelAlloy IN718 material data sheet — EOS GmbH (2022)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.