Inconel 718
Fasteners & Material Data
UNS N07718 · W.Nr. 2.4668
What is Inconel 718 and its applications?
Inconel 718 (UNS N07718) is an age-hardenable nickel-chromium alloy. Solution treatment and aging develop its strength. Its published uses include gas-turbine components, rocket and cryogenic equipment, fasteners and instrumentation.
- Aircraft and land-based gas turbines: Rings, casings and formed sheet-metal components.
- Rocket and cryogenic equipment: Liquid-fuel rocket components and cryogenic tankage.
- Fasteners and instrumentation: Threaded and precision components requiring a specified material condition.
Choose your 718 product
Engineering Application & Selection Guide
Inconel 718 is strengthened principally by niobium-rich gamma-double-prime (γ″) precipitates, with a contribution from gamma-prime (γ′). The solution and aging sequence controls the final structure; the UNS designation alone does not define a finished fastener condition.
- Inconel 718 stud bolts — For thermally cycled flanges, evaluate differential expansion, exposure time and retained clamp load. A room-temperature tensile result does not establish long-term preload retention.
- Inconel 718 socket head cap screws — For restricted-access cyclic joints, specify head geometry, thread-root condition and fatigue acceptance. Higher material strength does not prevent vibration loosening.
- Inconel 718 hex bolts — For bolted casings, match nut capacity, thread engagement and bearing area to the joint. Define lubricant and tightening conditions before setting preload.
When comparing Inconel 625 and 718 fasteners, separate corrosion requirements from strength requirements. Check the actual medium, temperature, stress and final condition. A producer temperature range is not an allowable bolting temperature or proof of retained clamp load.
Inconel 718 Composition
Composition limits · wt.%
- Ni
- 50–55%
- Cr
- 17–21%
- Nb + Ta
- 4.75–5.50%
- Mo
- 2.80–3.30%
- Ti
- 0.65–1.15%
- Al
- 0.20–0.80%
- Fe
- Balance
- C
- ≤0.08%
- Mn
- ≤0.35%
- Si
- ≤0.35%
- P
- ≤0.015%
- S
- ≤0.015%
- B
- ≤0.006%
- Cu
- ≤0.30%
- Co
- ≤1.0%
ASTM / ASME specifications by product form
Finished-product requirements
| Product | Reference |
|---|---|
| High-temperature bolting | ASTM A1014/A1014M / ASTM F2281 · specify the applicable grade, class and edition |
Fasteners · dimensional references
| Product | Reference |
|---|---|
| Hex bolts | ISO 4014 / ISO 4017 · ASME B18.2.1 |
| Threaded studs | DIN 976-1 · ASME B18.31.2 |
| Hex nuts | ISO 4032 · ASME B18.2.2 |
| Socket head screws | ISO 4762 · ASME B18.3 |
| Flat washers | ISO 7089 / ISO 7090 · ASME B18.21.1 |
| Custom fasteners | Customer drawing |
Raw-material specifications
| Product form / scope | Reference |
|---|---|
| Rod, bar & forgings | ASTM B637 / ASME SB637 · AMS 5662 / 5663 / 5664 |
| Wire & related wrought products | AMS 5832 / 5914 / 5962 |
| Plate, sheet & strip | ASTM B670 / B906 · ASME SB670 / SB906 · AMS 5596 / 5597 / 5950 |
| Pipe & tube | AMS 5589 / 5590 · DIN 17751 |
Dimensions do not define material or finished-part compliance. Specify the grade, condition and applicable requirements.
How to specify round bar, plate, wire and strip ↗Inconel 718 Mechanical Properties
Reference sample and condition
- Data basis
- Typical reference sample
- Test sample form
- Hot-rolled bar · Ø25.4 mm
- Sample size
- 1.0 in diameter (25.4 mm)
- Condition
- Annealed + aged
- Test temperature
- Room temperature
- Heat treatment
- 1750°F / 1 h, then 1325°F / 8 h; furnace cool to 1150°F for 18 h total aging.
- Test direction
- Longitudinal
| Key properties | Value |
|---|---|
| Tensile strength | 1389 MPa |
| 0.2% yield strength | 1207 MPa |
| Elongation | 20% |
Inconel 718 Physical Properties
| Property | Value | Unit |
|---|---|---|
| Density | 8.19 | g/cm³ |
| Melting range | 1260–1336 | °C |
Temperature curves and values
Plate · mill annealed + aged. 1325°F / 8 h, furnace cool to 1150°F / 8 h, air cool; total aging time 18 h.
Tensile and yield strength
Published table values
Haynes · 718 temperature data · Tensile Properties → Tensile Data, Plate ↗Elongation vs temperature
Published table values
Haynes · 718 temperature data · Tensile Properties → Tensile Data, Plate ↗Mechanical properties · plate
| Test temp. °C | Tensile MPa | Yield 0.2% MPa | Elong. % |
|---|---|---|---|
| RT | 1382 | 1157 | 20.6 |
| 427 | 1193 | 1027 | 22.6 |
| 538 | 1173 | 1006 | 21.8 |
| 649 | 1120 | 965 | 25.1 |
| 760 | 809 | 723 | 12.1 |
| 871 | 291 | 236 | 68.0 |
| 982 | 97 | 66 | 129.9 |
RT = room temperature · producer reference values, not design allowables or bar-sample results.
Haynes · 718 temperature data · Tensile Properties → Tensile Data, Plate ↗Specifications by product form ↓Procurement and application guide
Specify the material and final condition
Specify the heat treatment and strength requirement.
Material forms in the technical reference: Round bar · Flat bar · Wire · Plate · Sheet · Strip · Pipe & tube · Forging stock · Hexagon & sections.
Define the finished-part acceptance
Include the material or bolting specification, required final condition, dimensions and quantity. State the service medium, temperature and loading where known. Agree the required tests, inspection coverage and acceptance criteria for the finished part.
Start with the information you have
Send a drawing or share the product form and dimensions. Identify any undecided requirements for review rather than copying a typical property value into the purchase order.
Upload DrawingCondition-specific data
Catalogue minimums
A5 elongation, as labelled in the supplied table.
| Reference / condition | Tensile MPa | Yield 0.2% MPa | Elongation % | Reduction of area % | Hardness HB |
|---|---|---|---|---|---|
| ASTM B637 catalogue row | ≥1275 | ≥1034 | ≥12 | ≥15 | ≥331 |
Technical guides
All technical articles ↗
How to Specify Inconel 718 Fasteners
Inconel 625 vs 718: Which Is Better for Fasteners?
Inconel 718 Hardness: Heat Treatment, Scales and Bolt InspectionSelection and specification · 3
Installation and inspection · 4
Quality documents
EN 10204 3.1 MTC
Material certification and heat-number traceability
Mechanical testing
Methods and acceptance criteria follow the agreed specification
Alloy 718 laboratory report · PDF ↗Thread inspection
Sampled GO/NO-GO gauging for threaded products
Additional inspection and records
Heat-treatment records, PMI and third-party scope agreed per order
View PMI sample ↗Specify your Inconel 718 fastener
Sources and references
- Special Metals · Alloy 718 · SMC-045, September 2007 · Tables 1 & 8 ↗
- SAE · AMS 5662P · 2022 revision · public title and scope ↗
- SAE · AMS 5663P · 2022 revision · public title and scope ↗
- ASTM · B637 · B637-26 · public scope ↗
- Supplied technical reference · Scanned PDF page 4 · printed page 16
- Supplied technical reference · Scanned PDF page 12 · printed page 24
- Haynes · 718 temperature data · Tensile Properties → Tensile Data, Plate ↗
Additional published references
- DIN 17744 / 17750 / 17752–17754; ISO 6208 / 9723–9725; ASME Code Cases 1993 / 2206 / 2222 / N-62 / N-208 / N-253; AECMA PrEN 2404 / 2405 / 2407 / 2408 / 2952 / 2961 / 3219 / 3666 Special Metals · Alloy 718 · SMC-045, September 2007 · Tables 1 & 8 ↗
- NACE MR0175 / ISO 15156 Supplied technical reference · Scanned PDF page 12 · printed page 24
- AMS 5662: solution heat treated. AMS 5663: solution and precipitation heat treated. SAE · AMS 5663P · 2022 revision · public title and scope ↗