Project Description
N07725 / Inconel 725
UNS N07725 (Inconel 725) is a nickel-chromium-molybdenum-niobium PH superalloy delivering outstanding corrosion resistance alongside extremely high strength after aging — approximately twice that of annealed Alloy 625. Strength is achieved via heat treatment rather than cold work, enabling uniform strengthening of large or non-uniform sections.
Principal industries: oil & gas (sour-well completions), offshore/marine, chemical processing, and aerospace.
Similar Grades & Standards
| Standard | Designation | Scope |
|---|---|---|
| UNS | N07725 | Alloy chemistry identity |
| ASTM B805 | N07725 | Bar & wire — composition, dimensions, properties |
| ASME | Code Case 2217 | Bar & forging stock |
| NACE / ISO | MR0175 / ISO 15156 | Sour service (H₂S) approval |
| API | 6CRA | Corrosion-resistant alloys for oilfield equipment |
| JIS | NCF 725 | Nickel alloy bar & fasteners |
Closest compositional peers: Alloy 625 (N06625, EN 2.4856) — equivalent corrosion resistance, lower strength;
Alloy 718 (N07718) — similar strength, inferior marine corrosion resistance.
Applications by Industry
Tubing hangers, landing nipples, side pocket mandrels, polished bore receptacles,
subsurface safety valves, wellhead connectors, downhole completion tools
Propeller shafts, seawater pump shafts, marine studs & bolts,
subsea structural forgings, diving equipment hardware
Valve bodies, reactor vessel internals, piping flanges;
engine structural bolting, combustion liner components
Supply Forms & Sizes
| Form | Typical Size Range | Condition |
|---|---|---|
| Round Bar | Ø13 – Ø800 mm (0.5″–50″) | Annealed or Annealed+Aged |
| Flat Bar / Plate | Thickness 3–150 mm | Annealed or Annealed+Aged |
| Seamless Tube | OD 25–165 mm, WT 3–25 mm | Annealed or Annealed+Aged |
| Wire | Ø0.5 – Ø12 mm | Annealed |
| Forging Stock | Per customer specification | Hot-worked |
Chemical Composition
Per ASTM B805 / UNS N07725 (wt%)
| Ni | Cr | Mo | Nb+Ta | Ti | Al | C | Fe | |
|---|---|---|---|---|---|---|---|---|
| Min | 55.0 | 19.0 | 7.0 | 2.75 | 1.0 | — | — | Bal. |
| Max | 59.0 | 22.5 | 9.5 | 4.0 | 1.7 | 0.35 | 0.03 | Bal. |
Also: Si ≤0.20 | Mn ≤0.35 | P ≤0.015 | S ≤0.010 (wt%)
Mechanical Properties
Typical room-temperature mean values for hot-finished round bar (Special Metals data)
| Condition | YS (MPa) | UTS (MPa) | Elong. (%) | Hardness |
|---|---|---|---|---|
| Annealed (1038 °C / AC) | 427 | 855 | 57 | HRC 5 |
| Annealed + Aged (730 °C/8 h FC→620 °C/8 h AC) |
917 | 1241 | 30 | HRC 36 |
| Tube — Annealed + Aged | 921 | 1268 | 27 | HRC 39 |
RA (aged bar): ~36%. Approved under
NACE MR0175 / ISO 15156 for sour H₂S environments.
Values are mean data; actual results vary with thermo-mechanical processing.