Nickel Alloy Astroloy CAST-STA
Heat-treated state
UNS N13017
Coarse-grain cast form for static and small rotating parts where creep/stress-rupture at 800–870 °C matters more than ductility or LCF.
Values for the CAST-STA condition
Other Astroloy tempers and conditions
Astroloy is listed in 5 conditions; see the grade overview at Astroloy.
- SOL
- AS-HIP
- CAST-STA
- STA
- PM-HIP-STA
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution treated | Pick when rough machining or hot forming is required before the final ageing cycle; strength is much lower and must be restored by ageing. | 720 | 1,100 | 28 | 30 HRC | — |
Powder HIP consolidated, no final ageing | Near-net-shape HIP preforms supplied before final solution/age; used for machining allowance reduction, then heat treated. | 950 | 1,300 | 20 | 36 HRC | 1.3 % IACS |
CAST-STAThis page investment cast, solution treated and aged | Coarse-grain cast form for static and small rotating parts where creep/stress-rupture at 800–870 °C matters more than ductility or LCF. | 965 | 1,240 | 7 | 38 HRC | — |
STADefault Solution treated and aged | Standard wrought/forged disc condition (≈1150 °C solution, 870 °C stabilize, 980 °C + 650 °C/760 °C ageing) for maximum room- and mid-temperature strength. | 1,050 | 1,415 | 16 | 40 HRC | — |
powder consolidated (HIP/extruded-forged) and fully heat treated | Choose for turbine discs needing the highest low-cycle-fatigue life and uniform fine-grain properties in large sections. | 1,160 | 1,520 | 18 | 43 HRC | — |
What is Astroloy CAST-STA?
Astroloy CAST-STA is Astroloy heat treated to CAST-STA — coarse-grain cast form for static and small rotating parts where creep/stress-rupture at 800–870 °C matters more than ductility or LCF. Astroloy CAST-STA has a yield strength of 965 MPa (140 ksi) and a tensile strength of 1,240 MPa (180 ksi) — stronger than 95% of nickel alloy grades. Elongation at break is 7% and the elastic modulus is 213 GPa (30.9 Msi). Astroloy CAST-STA has a density of 7.91 g/cm³ (0.286 lb/in³), lighter than 89% of nickel alloy grades. It melts at 1,250°C (2,282 °F). STA is the default condition FabDigit quotes; CAST-STA is available on request or by drawing note.
Advantages
- High strength — 965 MPa (140 ksi), better than 95% of nickel alloy grades
Limitations
- Difficult to weld — 10/100, worse than 94% of nickel alloy grades
- Low fracture toughness — 55 MPa·√m (50.1 ksi·√in), worse than 93% of nickel alloy grades
- Difficult to machine — 10/100, worse than 93% of nickel alloy grades
- High embodied carbon — 16 kg CO₂/kg, worse than 93% of nickel alloy grades
- Limited ductility — 7%, worse than 88% of nickel alloy grades
Astroloy CAST-STA properties
Typical room-temperature values for Astroloy CAST-STA; 10 are specific to this condition. Other listed values are Astroloy reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
Astroloy CAST-STA has a density of 7.91 g/cm³ (0.286 lb/in³), lighter than 89% of nickel alloy grades. It melts at 1,250°C (2,282 °F).
Mechanical16
Astroloy CAST-STA has a yield strength of 965 MPa (140 ksi) and a tensile strength of 1,240 MPa (180 ksi) — stronger than 95% of nickel alloy grades. Elongation at break is 7% and the elastic modulus is 213 GPa (30.9 Msi).
Thermal6
Astroloy CAST-STA is rated for continuous service to 870°C (1,598 °F). It conducts heat at 11 W/m·K (6.36 BTU/hr·ft·°F), worse than 60% of nickel alloy grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
Astroloy CAST-STA conducts electricity at 1.3 % IACS, worse than 89% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), worse than 87% of nickel alloy grades.
Sustainability4
Producing a kilogram of Astroloy CAST-STA takes about 240 MJ of energy and emits 16 kg of CO₂ — more than 96% of nickel alloy grades. Typical recycled content is 15%.
Manufacturability8
Astroloy CAST-STA's machinability is not recommended (10/100, worse than 93% of nickel alloy grades); weldability not recommended (10/100); formability not recommended (8/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Astroloy CAST-STA
Is Astroloy easy to machine?
Very difficult in the aged condition — use rigid setups, low speeds (5–15 m/min carbide, 20–40 m/min ceramic), heavy positive feeds to avoid work-hardened skin, high-pressure coolant; finish grinding and creep-feed grinding are common for slots and fir-trees.
Can Astroloy be welded?
Essentially non-weldable in the fully aged state due to >40% γ′ strain-age cracking; if joining is unavoidable, weld in the solution-treated condition with electron beam or inertia friction welding and re-solution/age immediately.
Can Astroloy be formed, bent or molded?
Hot work only, in a narrow 1050–1150 °C window with tight strain-rate control (isothermal/superplastic forging for P/M billet); cold forming is impractical.
What surface finishes work on Astroloy?
Shot peen critical rotating surfaces for fatigue life; typical finishes are grinding plus passivation, aluminide diffusion or MCrAlY/TBC coatings for hot sections — anodizing does not apply.
Astroloy 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 |
|---|---|---|
| C | 0.04 – 0.1 | 0.06 |
| Cr | 14 – 16 | 15 |
| Co | 16 – 18.5 | 17 |
| Mo | 4.5 – 5.75 | 5.25 |
| Alγ′ former | 3.5 – 4.5 | 4 |
| Tiγ′ former | 3.35 – 3.85 | 3.5 |
| Bgrain-boundary strengthener | 0.02 – 0.04 | 0.03 |
| Zr | 0 – 0.1 | 0.06 |
| Feresidual | ≤ 1 | 0.3 |
| Mn | ≤ 0.15 | — |
| Si | ≤ 0.2 | — |
| S | ≤ 0.02 | — |
| Ni | balance | — |
Astroloy CAST-STA — frequently asked
What is Astroloy CAST-STA used for?
Astroloy CAST-STA is typically used for turbine discs, high-pressure turbine blades and critical rotating hardware. In short: highest-strength disc superalloy; powder-metallurgy HIP route; non-weldable when aged.
What is the yield strength of Astroloy CAST-STA?
Astroloy CAST-STA has a typical yield strength of 965 MPa (140 ksi) and a tensile strength of 1,240 MPa (180 ksi) — stronger than 95% of nickel alloy grades. Strength varies by condition: see the 5 listed tempers.
Is Astroloy CAST-STA easy to machine?
Not especially — machinability is rated not recommended (10/100, worse than 93% of nickel alloy grades). Very difficult in the aged condition — use rigid setups, low speeds (5–15 m/min carbide, 20–40 m/min ceramic), heavy positive feeds to avoid work-hardened skin, high-pressure coolant; finish grinding and creep-feed grinding are common for slots and fir-trees.
Can Astroloy CAST-STA be welded?
Not readily — weldability is rated not recommended (10/100). Essentially non-weldable in the fully aged state due to >40% γ′ strain-age cracking; if joining is unavoidable, weld in the solution-treated condition with electron beam or inertia friction welding and re-solution/age immediately.
What surface finishes work on Astroloy CAST-STA?
Shot peen critical rotating surfaces for fatigue life; typical finishes are grinding plus passivation, aluminide diffusion or MCrAlY/TBC coatings for hot sections — anodizing does not apply.
Can Astroloy CAST-STA be formed, bent or molded?
Hot work only, in a narrow 1050–1150 °C window with tight strain-rate control (isothermal/superplastic forging for P/M billet); cold forming is impractical.
What is the maximum service temperature of Astroloy CAST-STA?
Astroloy CAST-STA is rated for continuous use to about 870°C (1,598 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Astroloy-STA and Astroloy-SOL?
STA is the default condition — standard wrought/forged disc condition (≈1150 °C solution, 870 °C stabilize, 980 °C + 650 °C/760 °C ageing) for maximum room- and mid-temperature strength. SOL: pick when rough machining or hot forming is required before the final ageing cycle; strength is much lower and must be restored by ageing. Yield strength is 1,050 MPa in STA versus 720 MPa in SOL.
Sources
- ASM Specialty Handbook: Heat-Resistant Materials (Superalloys) — ASM International (1997)
- Superalloys II — High-Temperature Materials for Aerospace and Industrial Power — Wiley (1987)
- AMS 5880 / UNS N13017 nickel alloy bar and forgings — SAE International (2018)
- ASM Handbook Vol.16 Machining — Machining of Nickel Alloys — ASM International (1989)
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.