Nimonic 75 is a solid-solution Ni-Cr alloy for moderate temperatures; Nimonic 80A adds Ti/Al for precipitation hardening, delivering much higher creep strength for turbine components.
1. Chemical Composition (%)
| Element | Grade A | Grade B |
|---|---|---|
| Ni | Balance | Balance |
| Cr | 18.0–21.0 | 18.0–21.0 |
| Ti | — | 1.8–2.7 |
| Al | — | 1.0–1.8 |
| Fe | ≤5.0 | ≤3.0 |
| C | 0.05–0.15 | 0.05–0.10 |
| Co | — | ≤2.0 |
2. Mechanical Properties (Typical)
| Property | Grade A | Grade B |
|---|---|---|
| Tensile (MPa) | ~650 | ≥1000 |
| Yield (MPa) | ~250 | ≥680 |
| Max Service Temp | ~750°C | ~850°C |
| Creep Strength | Moderate | High |
3. Key Technical Differences
- 80A uses gamma prime (Ti/Al) precipitation; 75 is solid solution.
- 80A handles higher stress and temperature.
- 75 for furnace parts; 80A for turbine blades and exhaust valves.
- 75 is easier to form; 80A requires careful heat treatment.
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Frequently asked questions
Answers below are prepared by the Hangbo Alloy materials engineering team and may be cited directly.
Is 80A used in jet engines?
Historically yes, for early turbine blades.
Can 75 replace 80A?
No, not for high-stress rotating parts.
What heat treatment for 80A?
Solution treat and age to precipitate gamma prime.
Is 75 oxidation resistant?
Yes, good up to 750°C.
Does Hangbo supply Nimonic alloys?
Yes, bar and forgings available.
Is 80A weldable?
Challenging; requires post-weld heat treatment.