COMPREHENSIVE TECHNICAL ANALYSIS AND DATASHEET OF NIMONIC 80A (UNS N07080) FASTENING SYSTEMS
Nimonic 80A (officially designated as UNS N07080) is a wrought, age-hardenable nickel-chromium superalloy. Building directly upon the foundation of Nimonic 75, Alloy 80A is fortified with carefully controlled additions of Titanium and Aluminum. These elements allow the alloy to undergo precipitation hardening (the formation of the gamma-prime phase), drastically increasing its mechanical strength and creep-rupture resistance.
Designed to operate under extreme stress at elevated temperatures, Nimonic 80A maintains exceptional tensile strength and resists oxidation and scaling in continuous service environments up to 1500°F (815°C). It is universally specified for high-stress aerospace gas turbine components, heavy-duty marine diesel exhaust valves, and critical fastening applications in nuclear boiler support structures.
■ Product Overview & Specifications
Nimonic 80A fastening systems are typically supplied in the solution-treated and aged condition to guarantee optimal creep-rupture properties under high-temperature loading.
| Material Classification | Precipitation-Hardenable Nickel-Chromium Superalloy |
|---|---|
| UNS Designation | N07080 |
| Microstructure | Face-Centered Cubic (FCC) Austenitic matrix with Gamma-Prime precipitates |
| Magnetic State | Consistently Non-Magnetic |
| Density | ~8.19 g/cm³ (0.296 lb/in³) |
| Melting Range | 2480°F – 2534°F (1360°C – 1390°C) |
| Size Range | Metric: M6 to M80 | Imperial: 1/4" to 3" Custom forged turbine bolts and high-temp studs available. |
| Thread Types | UNC, UNF, Metric Coarse, Metric Fine (Rolled threads strictly recommended) |
■ Proprietary Datasheet Download (GATED)
Access professional-grade technical data for Nimonic 80A, including comprehensive Larson-Miller parameter charts, high-temperature fatigue data, and specialized multi-stage heat treatment cycles.
Nimonic 80A (N07080) — Complete Technical Datasheet
Contains specific stress-to-rupture thresholds for up to 30,000 hours at 700°C, thermal expansion coefficients across 10 temperature nodes, and aerospace AMS 5766 compliance metrics.
⬇ DOWNLOAD DATASHEET■ MTC Integration Section
To ensure structural integrity inside turbine engines and nuclear environments, precise chemical verification and heat treatment validation are paramount.
- EN 10204 Type 3.1: Detailed reporting of actual ladle chemical analysis, specifically verifying Titanium (Ti) and Aluminum (Al) levels for precipitation hardening, alongside final high-temperature creep test results.
- EN 10204 Type 3.2: Third-party witness testing facilitated for critical marine, nuclear, and aerospace turbine fastening components.
■ Chemical Composition (UNS N07080)
The addition of Aluminum and Titanium distinguishes Nimonic 80A from Nimonic 75. These elements combine with the high-nickel matrix during aging to form Ni3(Ti,Al) precipitates, locking the crystal lattice and providing immense high-temperature strength.
| Nickel (Ni) | Chromium (Cr) | Titanium (Ti) | Aluminum (Al) | Carbon (C) | Iron (Fe) | Cobalt (Co) |
|---|---|---|---|---|---|---|
| Balance (~76.0%) | 18.0 – 21.0 | 1.80 – 2.70 | 1.00 – 1.80 | 0.10 Max | 3.00 Max | 2.00 Max |
*Silicon and Manganese are restricted to 1.00% Max each. Trace elements like Boron (0.008% Max) and Zirconium (0.15% Max) are often included to improve creep performance.
■ Mechanical Properties & High-Temp Performance
After a rigorous two-step heat treatment (Solution Annealing followed by Precipitation Hardening), Nimonic 80A achieves formidable strength that it retains even as the metal glows red-hot.
| Property | Room Temperature (Aged) | At 1200°F (650°C) |
|---|---|---|
| Tensile Strength (Min) | 145 ksi (1000 MPa) | ~120 ksi (825 MPa) |
| Yield Strength (0.2% Offset, Min) | 87 ksi (600 MPa) | ~75 ksi (515 MPa) |
| Elongation in 2" (Min) | 20% | ~20% |
| Hardness | 250 to 350 HBW | N/A |
■ Equivalent Grades & Designations
| Standard / System | Designation |
|---|---|
| UNS Designation | N07080 |
| Common Trade Name | Nimonic 80A® (Trademark of Special Metals) |
| European Equivalent | W.Nr. 2.4952 / NiCr20TiAl |
| Aerospace Specs | AMS 5766, BS HR1, BS HR201 |
■ Applications & Industries
Nimonic 80A is the gold standard for dynamic, high-load environments where standard stainless steels and lower-tier nickel alloys would fail via creep elongation.
- Gas Turbines & Aerospace: Fastening systems for turbine rotor blades, combustion chamber rings, and exhaust nozzles.
- Marine & Automotive: High-performance exhaust valves for large marine diesel engines and motorsport vehicles.
- Nuclear Power: Boiler tube supports, heat exchanger structural bolting, and advanced gas-cooled reactor components.
- Industrial Furnaces: High-stress die-casting inserts, extrusion dies, and heavy-duty thermal processing fixtures.
■ Compatible Fastener Assemblies
To avoid metallurgical mismatch, thermal expansion shear forces, and severe thread galling, Nimonic 80A components must be carefully mated and heavily lubricated.
| External Threads (Nimonic 80A Studs/Bolts) | Recommended Mating Component (Nuts) |
|---|---|
| Nimonic 80A (Aged Condition) | Nimonic 80A Heavy Hex Nuts (Extreme high-temperature anti-seize required) |
| Nimonic 80A (Aged Condition) | Waspaloy or Inconel 718 Nuts (Acceptable for specialized aerospace pairing) |
■ Torque & Installation Guidelines
Nimonic 80A possesses high yield strength, allowing for significant clamping force. However, because it operates at temperatures where thread seizure is virtually guaranteed, ultra-high-temperature lubricants (such as ceramic paste, graphite, or pure Nickel anti-seize) must be used.
| Nominal Diameter | Threads Per Inch (UNC) | Target Torque — Lubricated (ft-lbs) |
|---|---|---|
| 3/8" | 16 | 30 - 40 |
| 1/2" | 13 | 65 - 80 |
| 5/8" | 11 | 135 - 160 |
| 3/4" | 10 | 240 - 280 |
■ Why Choose Ananka Group?
Ananka Group possesses the metallurgical expertise required to properly process precipitation-hardening superalloys, ensuring maximum performance without inducing micro-cracking.
- In-House Thermal Processing: We tightly control the 8-hour, 1080°C solution anneal followed by the 16-hour, 700°C precipitation aging cycle to ensure the perfect gamma-prime dispersion.
- Machining Before Aging: To ensure perfect thread profiles and avoid extreme tool wear, we can machine components in the softer, solution-treated state before performing the final hardening cycle.
- Traceability: 100% heat lot tracking mapped back to premium vacuum-melted superalloy billets.
- Rolled Thread Dynamics: Threads are rolled to maximize cyclic fatigue resistance, which is critical for turbine fastening applications.
■ Frequently Asked Questions
1. What does "Precipitation Hardenable" mean for Nimonic 80A?
Unlike standard stainless steels that harden only through cold-working, Nimonic 80A can be hardened by heat. When heated to around 700°C for an extended period, the Aluminum and Titanium atoms form microscopic particles (precipitates) within the metal lattice. These particles block atomic movement, making the metal incredibly strong and resistant to deformation.
2. How does Nimonic 80A differ from Inconel 718?
Both are precipitation-hardening superalloys. Inconel 718 relies on Niobium (Columbium) to form gamma-double-prime precipitates, while Nimonic 80A relies on Titanium/Aluminum to form gamma-prime precipitates. Inconel 718 is generally easier to weld and has slightly higher yield strength, but Nimonic 80A remains a classic, highly proven choice for gas turbine and marine exhaust environments.
3. Is Nimonic 80A resistant to high-temperature corrosion?
Yes. The high Chromium content (~20%) provides excellent resistance to oxidation and scaling up to 1000°C, and it is highly resistant to sulfur-containing atmospheres and vanadium pentoxide ash, which is why it is extensively used in marine diesel exhaust systems burning heavy fuel oil.
4. Can Nimonic 80A be welded?
Yes, but it is challenging. Because it is an age-hardenable alloy, it is susceptible to "strain-age cracking" during post-weld heat treatment. Welding must be performed in the fully solution-annealed state, followed by rapid cooling and meticulous re-aging under expert metallurgical control.