Bar and Rod
Plate and Sheet
Strip
Pipe and Tube
Wire
Welding
Powder Material
Cast Products
Forged Products
Fittings
Fastening
Round Bar:
φ2–500 mm, 1–6 m length
Flat/Square Bar:
4–100 mm thickness/width
Hex Bar:
A/F 3–100 mm
Hollow Bar:
OD 20–300 mm
Sheet:
0.3–6 mm thickness
Medium Plate:
6–25 mm thickness
Heavy Plate:
25–100 mm thickness
Standard Strip:
0.05–3 mm thick,
10–600 mm wide
Precision strip:
0.01–0.5 mm thick,
tight tolerance ±0.005 mm
Foil:
0.005–0.1 mm thick
Seamless Tube:
OD 6–450 mm,
WT 1–50 mm,
1–12 m length
Welded Tube:
OD 10–600 mm,
WT 1–20 mm
Capillary Tube:
OD 1–10 mm,
WT 0.1–2 mm
Wire Form:
Cold Drawn Wire,
Bright Wire,
Spring Wire,
Fine Wire,
Ultra-fine Wire
General Diameter:
φ0.1–10 mm
Coil Weight:
50–500 kg,
customizable tolerance
Solid Wire:
φ0.8–4.0 mm
Flux-cored Wire:
φ1.2–4.0 mm
Welding Rod:
φ2.0–5.0 mm
Powder Form:
AM 3D Printing Powder,
Spherical Powder,
Gas-atomized Powder,
Water-atomized Powder
Particle Size:
10–150 μm
Sphericity:
≥90% for AM grade
Cast Ingot:
φ200–800 mm
Precision Casting:
min wall 0.5 mm
Cast Pipe:
OD 100–600 mm,
WT 10–50 mm
Forged Bar:
Φ35–500 mm
Forged Ring:
OD 200–2000 mm
Forging Weight:
1–5000 kg
Fittings Form:
Elbow, Tee, Reducer, Flange, Cap, Outlet, Lap Joint
Size range:
1/2''–24'' (DN15–DN600)
Wall thickness:
Sch10–Sch160, STD, XS, XXS
Pressure Class:
150–2500 LB
Fastening Form:
Bolt, Nut, Screw, Stud, Washer, Pin, Rivet
Metric: M3–M64
Imperial: #4–2.5''
Length: 6–500 mm
Alloy 909 is an age-hardenable nickel-iron-cobalt controlled-expansion alloy. This datasheet presents the material within the American (ASTM / ASME / UNS) standard system.
A silicon-bearing member of the INCOLOY 900-series low-expansion alloys, Alloy 909 combines a constant low coefficient of thermal expansion, a constant modulus of elasticity and high strength. It is strengthened by precipitation of γ′ (Ni₃Ti) and eta-phase particles during ageing, with the nickel, cobalt and iron controlling the Curie temperature and low-expansion behaviour and the niobium, titanium and a deliberate silicon addition providing strength and improved notch stress-rupture properties without the need for an overageing treatment. The aluminium content is kept low. The alloy has good fabricability and is formed, machined and welded by conventional nickel-alloy procedures, behaving much like alloy 718 in most operations. It is used in the solution-treated and aged condition.
Typical applications include gas-turbine sealing systems, rings, casings, shafts and other clearance-control hardware, and superconductor sheathing.
| Property | Value | Unit |
|---|---|---|
| Density | 8.30 | g/cm³ |
| Inflection temperature | ~415 | °C |
| Elastic modulus | 159 | GPa |
| Coefficient of thermal expansion (20–425 °C) | 7.7 | µm/m·°C |
| Thermal conductivity (20 °C) | 14.8 | W/m·K |
| Specific heat (20 °C) | 427 | J/kg·K |
| Structure | Austenitic (FCC) | — |
| Element | Symbol | Min % | Max % | Role in Alloy |
|---|---|---|---|---|
| Iron | Fe | 38.0 | 44.0 | Base element; low-expansion matrix |
| Nickel | Ni | 36.0 | 40.0 | Controls expansion / Curie temperature; γ′ matrix |
| Cobalt | Co | 12.0 | 16.0 | Controls expansion; raises inflection temperature |
| Niobium | Nb | 4.30 | 5.20 | γ′ / eta precipitation strengthening |
| Titanium | Ti | 1.30 | 1.70 | γ′ (Ni₃Ti) precipitation strengthening |
| Silicon | Si | 0.25 | 0.50 | Improves notch stress-rupture properties |
| Aluminium | Al | — | 0.15 | Controlled low |
| Carbon | C | — | 0.06 | Carbide formation |
Age-hardened condition, typical values for AMS 5884 (UNS N19909).
| Condition | Property | Value |
|---|---|---|
| Solution treated & aged | Tensile strength (UTS) | ≥1069 MPa (155 ksi) |
| Solution treated & aged | 0.2% yield strength | ≥896 MPa (130 ksi) |
| Solution treated & aged | Elongation at break | ≥15 % |
| Solution treated & aged | Reduction of area | ≥25 % |
| — | Elastic modulus | 159 GPa |
Confirm against the mill test report. Bar to AMS 5884 is supplied solution-treated for machining, with final age hardening performed after machining to control dimensions and develop properties.
| Environment | Performance | Notes |
|---|---|---|
| Dimensional / thermal stability | Excellent | Constant low CTE; key design feature |
| High-temperature oxidation | Limited | Low chromium; coatings used for hot service |
| Aqueous / general | Moderate | Low chromium content |
| Notch stress-rupture | Very Good | Silicon addition; improved |
| Elevated-temperature strength | Excellent | Combined with low expansion |
The alloy is selected for its controlled expansion, constant modulus and high strength with improved notch stress-rupture behaviour rather than for corrosion resistance; the low chromium content limits high-temperature oxidation resistance, and protective coatings are commonly used for hot service.
A γ′ / eta precipitation-hardenable controlled-expansion alloy; strengthened by solution treatment followed by two-step ageing.
Solution Treatment Solution treat at approximately 982 °C (1800 °F) and water quench. Bar is normally supplied in this condition for machining.
Precipitation Hardening (Ageing) Age at approximately 720–760 °C (1325–1400 °F) for 8 hours, air cool, then re-age at approximately 620–650 °C (1150–1200 °F) for 8 hours, air cool — precipitating γ′ (Ni₃Ti) and eta-phase particles while locking in the controlled low-expansion microstructure. Ageing after machining controls final dimensions and develops properties.
Good weldability; readily welded by the gas-tungsten-arc process and other conventional nickel-alloy procedures, in the solution-annealed condition with post-weld ageing. Behaviour in most operations is similar to alloy 718.
| Welding Process | Applicability | Filler / Consumable |
|---|---|---|
| GTAW / TIG | Good | Matching alloy 909 filler |
| GMAW / MIG | Good | Matching filler |
| EBW / laser | Good | Autogenous or matching filler |
Weld in the solution-annealed condition; apply post-weld stress relief and ageing to develop properties.
Machining Guidelines
| Parameter | Recommendation |
|---|---|
| Preferred condition | Solution-treated for machining, then age |
| Machinability | Difficult; rigid setups, carbide tooling, slow speeds |
| Coolant | Ample coolant |
Forming Processes
| Process | Notes |
|---|---|
| Cold forming | Conventional techniques; good fabricability |
| Hot forming | Readily forged; solution and age afterward |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Aero gas turbine | Sealing systems, rings, casings, shafts | Low expansion + notch-rupture strength |
| Propulsion | Clearance-control hardware | Dimensional stability |
| Superconductors | Conductor sheathing | Low CTE + cryogenic behaviour |
| Aerospace | Constant-modulus / low-CTE parts | Stability + strength |
| Product Form | Standard / Designation | AMS |
|---|---|---|
| Bar and billet | UNS N19909 | AMS 5884 |
| Sheet and strip | UNS N19909 | AMS 5893 |
| Rod and wire | UNS N19909 | — |
| Material designation | UNS N19909 | Special Metals product |
Silicon-bearing nickel-iron-cobalt controlled-expansion alloy. UNS N19909.
| Alloy | Type | Si / Al | Strengthening | Best Used For |
|---|---|---|---|---|
| Alloy 909 | Ni-Fe-Co controlled expansion | Si-bearing, low Al | γ′ (Ni₃Ti) + eta | Low expansion + notch-rupture; turbine seals, superconductor sheath |
| Alloy 907 | Ni-Fe-Co controlled expansion | Si + restricted Al | γ′ / γ″ (Nb, Ti) | Improved notch-rupture low-expansion alloy |
| Alloy 903 | Ni-Fe-Co controlled expansion | Al-bearing | γ′ / γ″ (Nb, Ti, Al) | First-generation low-expansion alloy |
| Alloy 783 | Ni-Co-Fe + Al | Al-bearing | γ′ + β (NiAl) | Oxidation-resistant low-expansion alloy |
| Alloy 718 | Ni-Cr-Fe | — | γ′ + γ″ (Nb, Ti) | Most-used high-strength superalloy |
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