Nickel Alloy N09777-STA (Solution treated and aged)
Heat-treated state · default condition
UNS N09777
Standard delivered/engineering condition — full γ″/η precipitation strength with low, linear expansion for turbine casings, seals and rings.
Values for the STA condition
Other N09777 tempers and conditions
N09777 is listed in 4 conditions; see the grade overview at N09777.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Softest condition — choose for machining, cold forming, welding or forging stock before final ageing. | 480 | 830 | 35 | 200 HB | — |
Cold drawn | Cold-worked bar, wire or strip supplied for close tolerance and finish; age after machining to develop final properties. | 830 | 1,030 | 15 | 32 HRC | 1.7 % IACS |
STADefaultThis page Solution treated and aged | Standard delivered/engineering condition — full γ″/η precipitation strength with low, linear expansion for turbine casings, seals and rings. | 1,000 | 1,275 | 15 | 40 HRC | — |
Direct aged | Pick when the finer as-forged grain size is wanted for higher yield strength and fatigue life at some loss of ductility. | 1,100 | 1,380 | 12 | 43 HRC | — |
What is N09777-STA?
N09777-STA is N09777 heat treated to STA — standard delivered/engineering condition — full γ″/η precipitation strength with low, linear expansion for turbine casings, seals and rings. N09777-STA has a yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,275 MPa (185 ksi) — stronger than 95% of nickel alloy grades. Elongation at break is 15% and the elastic modulus is 160 GPa (23.2 Msi). N09777-STA has a density of 8.14 g/cm³ (0.294 lb/in³), lighter than 74% of nickel alloy grades. It melts at 1,345°C (2,453 °F).
Advantages
- High strength — 1,000 MPa (145 ksi), better than 95% of nickel alloy grades
- High electrical conductivity — 1.8 % IACS, better than 82% of nickel alloy grades
Limitations
- High embodied carbon — 17 kg CO₂/kg, worse than 96% of nickel alloy grades
- Needs corrosion protection — 40/100, worse than 95% of nickel alloy grades
- Low stiffness — 160 GPa (23.2 Msi), worse than 92% of nickel alloy grades
- Low fracture toughness — 70 MPa·√m (63.7 ksi·√in), worse than 85% of nickel alloy grades
- Limited ductility — 15%, worse than 81% of nickel alloy grades
N09777-STA properties
Typical room-temperature values for N09777-STA; 15 are specific to this condition. Other listed values are N09777 reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
N09777-STA has a density of 8.14 g/cm³ (0.294 lb/in³), lighter than 74% of nickel alloy grades. It melts at 1,345°C (2,453 °F).
Mechanical14
N09777-STA has a yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,275 MPa (185 ksi) — stronger than 95% of nickel alloy grades. Elongation at break is 15% and the elastic modulus is 160 GPa (23.2 Msi).
Thermal6
N09777-STA is rated for continuous service to 650°C (1,202 °F). It conducts heat at 13 W/m·K (7.51 BTU/hr·ft·°F), better than 71% of nickel alloy grades. Thermal expansion is 7.4 µm/m·K (4.11 µin/in·°F).
Electrical3
N09777-STA conducts electricity at 1.8 % IACS, better than 82% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is fair (40/100), worse than 95% of nickel alloy grades.
Sustainability4
Producing a kilogram of N09777-STA takes about 230 MJ of energy and emits 17 kg of CO₂ — more than 91% of nickel alloy grades. Typical recycled content is 25%.
Manufacturability7
N09777-STA's machinability is poor (22/100, better than 64% of nickel alloy grades); weldability fair (45/100); 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 N09777-STA
Is N09777 easy to machine?
Machine in the solution-annealed state where possible; rigid setups, positive-rake carbide or ceramic tools, low surface speed (~15–25 m/min carbide in aged material), heavy feed and flood coolant to avoid work hardening and glazing.
Can N09777 be welded?
GTAW/EBW in the solution-annealed condition with matched or Nb-bearing filler; keep heat input low, avoid restraint, and re-solution + double age after welding to restore strength and expansion behaviour.
Can N09777 be formed, bent or molded?
Hot work 900–1120 °C with finishing below 1010 °C for fine grain; cold forming only from the annealed condition with intermediate anneals — aged material is essentially non-formable.
What surface finishes work on N09777?
Not anodizable; grind/polish with the low thermal conductivity in mind, and use aluminide, thermal-barrier or plated coatings where wet-corrosion or long-term oxidation protection is required.
N09777 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 |
|---|---|---|
| Ni | 24 – 26 | 25 |
| Co | 28 – 31 | 29 |
| Cradded for oxidation / SAGBO resistance | 5 – 6 | 5.5 |
| Nbprincipal γ″ former (Nb+Ta) | 4.4 – 5.2 | 4.8 |
| Ti | 0.6 – 1 | 0.85 |
| Al | 0.3 – 0.7 | 0.5 |
| Si | 0.15 – 0.5 | 0.35 |
| C | ≤ 0.05 | 0.03 |
| Mn | ≤ 0.5 | — |
| B | ≤ 0.01 | 0.01 |
| P | ≤ 0.02 | — |
| S | ≤ 0.02 | — |
| Febalance, approx. 32–36 % | balance | — |
N09777-STA — frequently asked
What is N09777-STA used for?
N09777-STA is typically used for gas turbine casings, seal rings and aerospace low-expansion structural parts. In short: low expansion, high strength; aged to 40 HRC; needs coatings for corrosion.
What is the yield strength of N09777-STA?
N09777-STA has a typical yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,275 MPa (185 ksi) — stronger than 95% of nickel alloy grades. Strength varies by condition: see the 4 listed tempers.
Is N09777-STA easy to machine?
Not especially — machinability is rated poor (22/100, better than 64% of nickel alloy grades). Machine in the solution-annealed state where possible; rigid setups, positive-rake carbide or ceramic tools, low surface speed (~15–25 m/min carbide in aged material), heavy feed and flood coolant to avoid work hardening and glazing.
Can N09777-STA be welded?
With care — weldability is rated fair (45/100). GTAW/EBW in the solution-annealed condition with matched or Nb-bearing filler; keep heat input low, avoid restraint, and re-solution + double age after welding to restore strength and expansion behaviour.
What surface finishes work on N09777-STA?
Not anodizable; grind/polish with the low thermal conductivity in mind, and use aluminide, thermal-barrier or plated coatings where wet-corrosion or long-term oxidation protection is required.
Can N09777-STA be formed, bent or molded?
Hot work 900–1120 °C with finishing below 1010 °C for fine grain; cold forming only from the annealed condition with intermediate anneals — aged material is essentially non-formable.
What is the maximum service temperature of N09777-STA?
N09777-STA is rated for continuous use to about 650°C (1,202 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between N09777-STA and N09777-SA?
STA is the default condition — standard delivered/engineering condition — full γ″/η precipitation strength with low, linear expansion for turbine casings, seals and rings. SA: softest condition — choose for machining, cold forming, welding or forging stock before final ageing. Yield strength is 1,000 MPa in STA versus 480 MPa in SA.
Sources
- Controlled-expansion Fe-Ni-Co-Cr superalloy (Thermo-Span type) technical datasheet — Carpenter Technology (2020)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (low-expansion superalloys) — ASM International (1990)
- ASM Specialty Handbook: Heat-Resistant Materials — ASM International (1997)
- Metals & Alloys in the Unified Numbering System (UNS N09777) — SAE/ASTM (2017)
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.