Materials / Superalloy
Inconel 718
- UNS
- N07718
- W.Nr
- 2.4668
- EN
- NiCr19Fe19Nb5Mo3
A precipitation-hardening nickel-iron-chromium superalloy. Its properties come from a controlled solution and ageing cycle, which means the heat treatment matters as much as the chemistry.
Composition
| Element | Min | Max |
|---|---|---|
| Ni | 50.0 | 55.0 |
| Cr | 17.0 | 21.0 |
| Nb+Ta | 4.75 | 5.50 |
| Mo | 2.80 | 3.30 |
| Ti | 0.65 | 1.15 |
| Al | 0.20 | 0.80 |
| Co | — | 1.0 |
| C | — | 0.08 |
| Fe | — | bal |
Per cent by weight, to the governing standard.
- Ni52.5
- Cr19.0
- Fe18.9
- Nb+Ta5.1
- Mo3.0
- Ti0.9
- Al0.5
Per cent by weight, at the midpoint of each specified window. Elements given only as a maximum have no midpoint to take, so they sit inside the balance rather than being estimated; trace elements below 0.5 % are not shown. Indicative only; the composition table above and the governing standard are what define the limits.
Mechanical
- Tensile strength, min
- 1276 MPa
- Yield strength (0.2%), min
- 1034 MPa
- Elongation, min
- 12 %
- Condition
- Solution treated & aged, ASTM B637 — condition to be specified on order
Standards by form
| Bar, forgings & rings | ASTM B637 | |
|---|---|---|
| Plate, sheet & strip | ASTM B670 | |
| Forgings | ASTM B564 |
Where it is specified
- High-strength service to roughly 700 °C
- Downhole tooling, valves, turbine components, fasteners
- Good weldability for a precipitation-hardened alloy — resists post-weld strain-age cracking
Chemistry proves nothing here; the heat treatment is the grade
718 is the grade where chemistry alone proves nothing. An under-aged or incorrectly solution-treated heat has textbook composition and will not make its mechanical minimums. Certificates showing chemistry but vague heat-treatment records are the warning sign.
What we specify and check
- Heat treatment records demanded and read, not just filed
- Hardness and tensile verification on the delivered heat
- PMI confirming Nb+Ta and Ti against B637
- Grain size where the application is fatigue-driven
We commission an accredited independent laboratory to test the heat before the material leaves China. You will receive that report unedited, whether it passes or not.
Request Inconel 718
Tell us the form, dimensions and service conditions. We reply with availability, indicative landed price, lead time and the test regime we would specify for your application.
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