N07752 is a precipitation-hardenable nickel-chromium superalloy of the X-750 type, a UNS composition variant offering high strength and excellent corrosion and oxidation resistance over a wide temperature range. This datasheet presents the material within the American (ASTM / ASME / UNS) standard system.
Essentially the corrosion- and oxidation-resistant nickel-chromium base of alloy 600 made precipitation-hardenable by additions of aluminium and titanium, N07752 develops its strength from the gamma-prime (γ′, Ni₃(Al,Ti)) phase during ageing. It provides high strength up to about 700 °C (1300 °F) — with useful strength retained to about 980 °C (1800 °F) — together with excellent properties down to cryogenic temperatures, good relaxation resistance for springs, and good corrosion and oxidation resistance. It is used in the solution-treated and aged condition, with the heat-treatment schedule selected for the application (spring temper, gas-turbine or nuclear service).
Typical applications include gas-turbine components, high-temperature springs and fasteners, nuclear-reactor jet-pump beams and internals, bolts, forming tools and rocket-engine hardware.
| Property | Value | Unit |
|---|---|---|
| Density | 8.28 | g/cm³ |
| Melting range | 1390–1430 | °C |
| Elastic modulus | 214 | GPa |
| Coefficient of thermal expansion (20–100 °C) | 12.6 | µm/m·°C |
| Thermal conductivity (20 °C) | 12.0 | W/m·K |
| Specific heat (20 °C) | 431 | J/kg·K |
| Structure | Austenitic (FCC) | — |
| Element | Symbol | Min % | Max % | Role in Alloy |
|---|---|---|---|---|
| Nickel | Ni | 70.0 | — | Base element; γ′ matrix |
| Chromium | Cr | 14.0 | 17.0 | Oxidation / corrosion resistance |
| Iron | Fe | 5.00 | 9.00 | Solid-solution element |
| Titanium | Ti | 2.25 | 2.75 | γ′ (Ni₃Ti) precipitation strengthening |
| Niobium | Nb (+Ta) | 0.70 | 1.20 | γ′ / carbide strengthening |
| Aluminium | Al | 0.40 | 1.00 | γ′ formation |
| Manganese | Mn | — | 1.00 | Deoxidiser |
| Silicon | Si | — | 0.50 | Deoxidiser |
| Carbon | C | — | 0.08 | Carbide formation |
| Cobalt | Co | — | 1.00 | Residual |
| Copper | Cu | — | 0.50 | Residual |
Solution-treated and aged condition, typical values for UNS N07752.
| Condition | Property | Value |
|---|---|---|
| Solution treated & aged | Tensile strength (UTS) | ≥1100 MPa (160 ksi) |
| Solution treated & aged | 0.2% yield strength | ≥690 MPa (100 ksi) |
| Solution treated & aged | Elongation at break | ≥20 % |
| Solution treated & aged | Reduction of area | ≥25 % |
| Solution treated & aged | Hardness | ~30–40 HRC |
Confirm against the mill test report. Properties depend on the solution and ageing schedule selected for the application.
| Environment | Performance | Notes |
|---|---|---|
| High-temperature oxidation | Excellent | Passivating chromium oxide |
| Aqueous / general | Good | Chromium-bearing |
| Steam / nuclear water | Good | Note SCC risk in high-temperature pure water |
| Cryogenic | Excellent | Retains strength and toughness |
| Relaxation (springs) | Excellent | Maintains spring force at temperature |
Corrosion and oxidation resistance is good across a wide temperature range; in high-temperature pure water (e.g. reactor service) attention must be given to intergranular stress-corrosion cracking and the appropriate heat treatment selected.
A γ′ precipitation-hardenable superalloy; strengthened by solution treatment followed by ageing. The schedule is chosen for the application.
Solution Treatment Solution anneal at approximately 1095–1150 °C (for maximum creep-rupture strength) or ~980 °C for spring and general grades, then cool.
Precipitation Hardening (Ageing) Age to precipitate γ′ (Ni₃(Al,Ti)) — for example a single age near 730 °C / ~20 h, or an equalised/double age (~885 °C then ~705 °C) for high-temperature service; spring tempers use ~650–730 °C. Select per the relevant AMS specification.
Weldable by inert-gas processes; welding is generally done in the solution-annealed condition with post-weld solution and ageing. As a γ′ alloy it requires care to avoid strain-age cracking.
| Welding Process | Applicability | Filler / Consumable |
|---|---|---|
| GTAW / TIG | Acceptable | Matching X-750 / compatible filler |
| GMAW / MIG | Acceptable | Matching filler |
| Resistance / spot | Good | — |
Weld in the solution-annealed condition; apply post-weld solution and ageing to develop properties.
Machining Guidelines
| Parameter | Recommendation |
|---|---|
| Preferred condition | Solution-annealed for machining, then age |
| Machinability | Difficult; rigid setups, carbide tooling, slow speeds |
| Coolant | Ample coolant |
Forming Processes
| Process | Notes |
|---|---|
| Cold forming | In the annealed condition; work-hardens; spring tempers cold-coiled |
| Hot forming | Performed hot; solution and age afterward |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Gas turbine | Blades, discs, rings, bolts | Strength + oxidation resistance |
| Springs / fasteners | High-temperature springs, bolts | Strength + relaxation resistance |
| Nuclear | Jet-pump beams, internals, springs | Strength + controlled SCC behaviour |
| Aerospace / cryogenic | Rocket hardware, cryogenic parts | Strength across temperature range |
| Product Form | ASTM Standard | AMS |
|---|---|---|
| Bar, rod and wire | ASTM B637 | AMS 5667 / 5668 / 5671 |
| Spring wire and strip | ASTM B637 | AMS 5698 / 5699 |
| Forgings | ASTM B637 | AMS 5670 |
| Material designation | UNS N07752 | X-750-type variant |
Nickel-chromium precipitation-hardenable superalloy (X-750 type). UNS N07752.
| UNS | Ni % | Cr % | Strengthening | Best Used For |
|---|---|---|---|---|
| N07752 | ≥70 | 14–17 | γ′ (Al, Ti) | X-750-type Ni-Cr γ′ alloy; corrosion + high strength to ~700 °C |
| N07750 | ≥70 | 14–17 | γ′ (Al, Ti) | X-750 standard composition |
| N06600 | ≥72 | 14–17 | Solid solution | General-purpose Ni-Cr-Fe alloy (600) |
| N07718 | 50–55 | 17–21 | γ′ + γ″ (Nb, Ti) | Most-used high-strength superalloy (718) |
| N07090 | Balance | 18–21 | γ′ (Al, Ti) | Gas-turbine blades and rings (Nimonic 90) |




