Nickel Alloy Nimonic 90-STA (Solution treated and aged)
Heat-treated state · default condition
UNS N07090 · EN 2.4632, NiCr20Co18Ti
Standard service condition for turbine blades, discs, rings and bolts requiring full γ′ strength to ~900 °C.
Values for the STA condition
Other Nimonic 90 tempers and conditions
Nimonic 90 is listed in 5 conditions; see the grade overview at Nimonic 90.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Softened / annealed | Most ductile condition; choose for deep drawing, bending or spinning of sheet before ageing. | 360 | 850 | 50 | 10 HRC | 1.4 % IACS |
Solution annealed | Supply condition for parts that will be machined or formed before final ageing. | 400 | 880 | 45 | 200 HB | — |
STADefaultThis page Solution treated and aged | Standard service condition for turbine blades, discs, rings and bolts requiring full γ′ strength to ~900 °C. | 810 | 1,240 | 27 | 35 HRC | — |
Cold drawn | Cold-drawn stock for close-tolerance small bar and wire that will be aged after fabrication. | 850 | 1,100 | 18 | 34 HRC | 1.5 % IACS |
Hard drawn spring wire | For high-temperature springs and fasteners where maximum room-temperature strength and relaxation resistance are needed. | 1,200 | 1,450 | 8 | 44 HRC | 1.5 % IACS |
What is Nimonic 90-STA?
Nimonic 90-STA is Nimonic 90 heat treated to STA — standard service condition for turbine blades, discs, rings and bolts requiring full γ′ strength to ~900 °C. Nimonic 90-STA has a yield strength of 810 MPa (117 ksi) and a tensile strength of 1,240 MPa (180 ksi) — stronger than 84% of nickel alloy grades. Elongation at break is 27% and the elastic modulus is 213 GPa (30.9 Msi). Nimonic 90-STA has a density of 8.19 g/cm³ (0.296 lb/in³), lighter than 68% of nickel alloy grades. It melts at 1,310°C (2,390 °F).
Advantages
- High strength — 810 MPa (117 ksi), better than 84% of nickel alloy grades
Limitations
- High embodied carbon — 16 kg CO₂/kg, worse than 93% of nickel alloy grades
- Difficult to weld — 25/100, worse than 82% of nickel alloy grades
- Limited formability — 20/100, worse than 75% of nickel alloy grades
Nimonic 90-STA properties
Typical room-temperature values for Nimonic 90-STA; 14 are specific to this condition. Other listed values are Nimonic 90 reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
Nimonic 90-STA has a density of 8.19 g/cm³ (0.296 lb/in³), lighter than 68% of nickel alloy grades. It melts at 1,310°C (2,390 °F).
Mechanical16
Nimonic 90-STA has a yield strength of 810 MPa (117 ksi) and a tensile strength of 1,240 MPa (180 ksi) — stronger than 84% of nickel alloy grades. Elongation at break is 27% and the elastic modulus is 213 GPa (30.9 Msi).
Thermal5
Nimonic 90-STA is rated for continuous service to 920°C (1,688 °F). It conducts heat at 11.5 W/m·K (6.64 BTU/hr·ft·°F), better than 57% of nickel alloy grades. Thermal expansion is 12.7 µm/m·K (7.06 µin/in·°F).
Electrical3
Nimonic 90-STA conducts electricity at 1.5 % IACS, better than 59% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (72/100), worse than 71% of nickel alloy grades.
Sustainability4
Producing a kilogram of Nimonic 90-STA takes about 240 MJ of energy and emits 16 kg of CO₂ — more than 96% of nickel alloy grades. Typical recycled content is 30%.
Manufacturability8
Nimonic 90-STA's machinability is not recommended (14/100, worse than 81% of nickel alloy grades); weldability poor (25/100); formability poor (20/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Nimonic 90-STA
Is Nimonic 90 easy to machine?
Machine preferably in the solution-treated condition with rigid setups, positive-rake carbide or ceramic tooling, low speeds (15–25 m/min carbide), heavy constant feed and flood coolant to avoid work hardening and glazing.
Can Nimonic 90 be welded?
GTAW/EB weld in the solution-treated state using matching or Ni-Cr filler, then re-solution and age; welding aged material risks γ′ strain-age cracking in the HAZ.
Can Nimonic 90 be formed, bent or molded?
Hot work at 1050–1180 °C with frequent reheats; cold forming only from the softened condition with high forces and interstage anneals.
What surface finishes work on Nimonic 90?
Descale by grit blasting plus HF-HNO₃ pickling; can be electropolished or fine ground, and aluminide/MCrAlY or thermal-barrier coatings are used for hot-gas-path parts (no anodizing).
Nimonic 90 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Cr | 18 – 21 | 19.5 |
| Co | 15 – 21 | 18 |
| Tiγ′ former | 1.8 – 3 | 2.4 |
| Alγ′ former | 1 – 2 | 1.4 |
| Fe | ≤ 1.5 | 0.5 |
| Mn | ≤ 1 | 0.3 |
| Si | ≤ 1 | 0.3 |
| C | ≤ 0.13 | 0.07 |
| Cu | ≤ 0.2 | 0.05 |
| Zr | ≤ 0.15 | 0.06 |
| B | ≤ 0.02 | 0.01 |
| S | ≤ 0.02 | 0 |
| Nibalance, plus Co | balance | — |
Nimonic 90-STA — frequently asked
What is Nimonic 90-STA used for?
Nimonic 90-STA is typically used for turbine blades, turbine discs, exhaust valves and high-temperature springs and fasteners. In short: classic gas-turbine Nimonic; 920 °C creep strength; gamma-prime hardened Ni-Cr-Co.
What is the yield strength of Nimonic 90-STA?
Nimonic 90-STA has a typical yield strength of 810 MPa (117 ksi) and a tensile strength of 1,240 MPa (180 ksi) — stronger than 84% of nickel alloy grades. Strength varies by condition: see the 5 listed tempers.
Is Nimonic 90-STA easy to machine?
Not especially — machinability is rated not recommended (14/100, worse than 81% of nickel alloy grades). Machine preferably in the solution-treated condition with rigid setups, positive-rake carbide or ceramic tooling, low speeds (15–25 m/min carbide), heavy constant feed and flood coolant to avoid work hardening and glazing.
Can Nimonic 90-STA be welded?
Not readily — weldability is rated poor (25/100). GTAW/EB weld in the solution-treated state using matching or Ni-Cr filler, then re-solution and age; welding aged material risks γ′ strain-age cracking in the HAZ.
What surface finishes work on Nimonic 90-STA?
Descale by grit blasting plus HF-HNO₃ pickling; can be electropolished or fine ground, and aluminide/MCrAlY or thermal-barrier coatings are used for hot-gas-path parts (no anodizing).
Can Nimonic 90-STA be formed, bent or molded?
Hot work at 1050–1180 °C with frequent reheats; cold forming only from the softened condition with high forces and interstage anneals.
What is the maximum service temperature of Nimonic 90-STA?
Nimonic 90-STA is rated for continuous use to about 920°C (1,688 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Nimonic 90-STA and Nimonic 90 SOFT?
STA is the default condition — standard service condition for turbine blades, discs, rings and bolts requiring full γ′ strength to ~900 °C. SOFT: most ductile condition; choose for deep drawing, bending or spinning of sheet before ageing. Yield strength is 810 MPa in STA versus 360 MPa in SOFT.
Sources
- NIMONIC alloy 90 technical datasheet — Special Metals Corporation (2007)
- AMS 5829 — Nickel Alloy Bars, Forgings and Rings, 57Ni-19.5Cr-18Co-2.4Ti-1.4Al — SAE International (2018)
- BS HR 501/HR 601 (Nimonic 90 bar and sheet) — BSI (1991)
- ASM Specialty Handbook: Heat-Resistant Materials / ASM Handbook Vol.1 — ASM International (1997)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.