Nickel Alloy Nimonic 80A-STA (Solution treated and aged)
Heat-treated state · default condition
UNS N07080 · EN 2.4631, 2.4952 · GB GH4080A
Standard commercial bar/forging condition — the best all-round strength/ductility balance for fasteners, valves and hot tooling to ~815 °C.
Values for the STA condition
Other Nimonic 80A tempers and conditions
Nimonic 80A is listed in 5 conditions; see the grade overview at Nimonic 80A.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Softest supply condition — pick it for machining, deep forming or bending before the customer performs the ageing treatment. | 320 | 800 | 45 | 185 HB | — |
1080 °C/8 h AC + 850 °C/24 h AC stabilise + 700 °C/16 h AC | Triple heat treatment for turbine blades/rings that see prolonged 750–850 °C service — trades a little room-temperature strength for microstructural stability and creep life. | 640 | 1,010 | 30 | 30 HRC | 1.4 % IACS |
STADefaultThis page Solution treated and aged | Standard commercial bar/forging condition — the best all-round strength/ductility balance for fasteners, valves and hot tooling to ~815 °C. | 700 | 1,100 | 27 | 33 HRC | — |
Hot forged / hot rolled and precipitation hardened | Valve-head and hot-forged part condition specified by hardness — used for exhaust valves and hot-work punches where a 300–380 HB forged body is required. | 730 | 1,120 | 22 | 36 HRC | 1.4 % IACS |
Cold drawn bar/wire, then aged 700 °C/16 h | Highest-strength small-section product (bolts, springs, wire) — cold work plus ageing raises strength but ductility and weldability drop sharply. | 900 | 1,230 | 15 | 38 HRC | — |
What is Nimonic 80A-STA?
Nimonic 80A-STA is Nimonic 80A heat treated to STA — standard commercial bar/forging condition — the best all-round strength/ductility balance for fasteners, valves and hot tooling to ~815 °C. Nimonic 80A-STA has a yield strength of 700 MPa (102 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 81% of nickel alloy grades. Elongation at break is 27% and the elastic modulus is 222 GPa (32.2 Msi). Nimonic 80A-STA has a density of 8.19 g/cm³ (0.296 lb/in³), lighter than 68% of nickel alloy grades. It melts at 1,360°C (2,480 °F).
Advantages
- High strength — 700 MPa (102 ksi), better than 81% of nickel alloy grades
Limitations
- Difficult to weld — 30/100, worse than 78% of nickel alloy grades
Nimonic 80A-STA properties
Typical room-temperature values for Nimonic 80A-STA; 14 are specific to this condition. Other listed values are Nimonic 80A reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
Nimonic 80A-STA has a density of 8.19 g/cm³ (0.296 lb/in³), lighter than 68% of nickel alloy grades. It melts at 1,360°C (2,480 °F).
Mechanical15
Nimonic 80A-STA has a yield strength of 700 MPa (102 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 81% of nickel alloy grades. Elongation at break is 27% and the elastic modulus is 222 GPa (32.2 Msi).
Thermal6
Nimonic 80A-STA is rated for continuous service to 815°C (1,499 °F). It conducts heat at 11.2 W/m·K (6.47 BTU/hr·ft·°F), worse than 52% of nickel alloy grades. Thermal expansion is 12.7 µm/m·K (7.06 µin/in·°F).
Electrical3
Nimonic 80A-STA conducts electricity at 1.4 % IACS, worse than 65% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (75/100), worse than 63% of nickel alloy grades.
Sustainability4
Producing a kilogram of Nimonic 80A-STA takes about 200 MJ of energy and emits 13.5 kg of CO₂ — more than 78% of nickel alloy grades. Typical recycled content is 35%.
Manufacturability6
Nimonic 80A-STA's machinability is poor (15/100, worse than 76% of nickel alloy grades); weldability poor (30/100); formability poor (30/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Nimonic 80A-STA
Is Nimonic 80A easy to machine?
Machine preferably in the solution-treated state with rigid setups, positive-rake carbide or ceramic tooling, low speed/heavy feed and flood coolant; never dwell — the alloy work-hardens instantly and glazes the cut.
Can Nimonic 80A be welded?
GTAW/EB weld in the solution-treated condition using matching or Ni-Cr-Ti filler, low heat input and no interpass overheating, then re-solution and age; direct welding of aged material risks strain-age (γ′ reheat) cracking.
Can Nimonic 80A be formed, bent or molded?
Hot work at 1050–1150 °C with frequent reheats; cold forming only from the annealed condition with heavy tooling and interstage anneals at 1080 °C due to the very high work-hardening rate.
What surface finishes work on Nimonic 80A?
Grit-blast or pickle in HNO₃-HF to remove the tenacious Cr/Ti/Al oxide before brazing, plating or NDT; it takes a good mechanical polish, and no anodizing applies (n/a for Ni alloys).
Nimonic 80A 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 |
| Tiγ′ former | 1.8 – 2.7 | 2.4 |
| Alγ′ former | 1 – 1.8 | 1.4 |
| Fe | ≤ 3 | 1 |
| Co | ≤ 2 | 0.5 |
| Mn | ≤ 1 | 0.3 |
| Si | ≤ 1 | 0.3 |
| C | ≤ 0.1 | 0.06 |
| Cu | ≤ 0.2 | 0.05 |
| Zr | ≤ 0.15 | 0.05 |
| B | ≤ 0.01 | 0 |
| S | ≤ 0.02 | 0.01 |
| Nibalance, plus Co counted with Ni in some specs | ≥ 65 (balance) | — |
Nimonic 80A-STA — frequently asked
What is Nimonic 80A-STA used for?
Nimonic 80A-STA is typically used for turbine blades (early designs), exhaust valves and high-temperature springs and fasteners. In short: classic γ′-hardened Ni-Cr alloy; 815 °C service capability; very low machinability rating.
What is the yield strength of Nimonic 80A-STA?
Nimonic 80A-STA has a typical yield strength of 700 MPa (102 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 81% of nickel alloy grades. Strength varies by condition: see the 5 listed tempers.
Is Nimonic 80A-STA easy to machine?
Not especially — machinability is rated poor (15/100, worse than 76% of nickel alloy grades). Machine preferably in the solution-treated state with rigid setups, positive-rake carbide or ceramic tooling, low speed/heavy feed and flood coolant; never dwell — the alloy work-hardens instantly and glazes the cut.
Can Nimonic 80A-STA be welded?
Not readily — weldability is rated poor (30/100). GTAW/EB weld in the solution-treated condition using matching or Ni-Cr-Ti filler, low heat input and no interpass overheating, then re-solution and age; direct welding of aged material risks strain-age (γ′ reheat) cracking.
What surface finishes work on Nimonic 80A-STA?
Grit-blast or pickle in HNO₃-HF to remove the tenacious Cr/Ti/Al oxide before brazing, plating or NDT; it takes a good mechanical polish, and no anodizing applies (n/a for Ni alloys).
Can Nimonic 80A-STA be formed, bent or molded?
Hot work at 1050–1150 °C with frequent reheats; cold forming only from the annealed condition with heavy tooling and interstage anneals at 1080 °C due to the very high work-hardening rate.
What is the maximum service temperature of Nimonic 80A-STA?
Nimonic 80A-STA is rated for continuous use to about 815°C (1,499 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Nimonic 80A-STA and Nimonic 80A-ST?
STA is the default condition — standard commercial bar/forging condition — the best all-round strength/ductility balance for fasteners, valves and hot tooling to ~815 °C. ST: softest supply condition — pick it for machining, deep forming or bending before the customer performs the ageing treatment. Yield strength is 700 MPa in STA versus 320 MPa in ST.
Sources
- NIMONIC alloy 80A technical bulletin — Special Metals Corporation (2004)
- BS 3076 / HR 1 – Nickel and nickel alloy bar (NA20) — BSI (1989)
- EN 10090 Valve steels and alloys for internal combustion engines (NiCr20TiAl, 2.4952) — CEN (1998)
- GB/T 14992 / GH4080A high-temperature alloy designations — SAC (2005)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Superalloys: A Technical Guide, 2nd ed. — ASM International (2002)
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.