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
Incoloy 907 is an age-hardenable nickel-iron-cobalt controlled-expansion alloy. This datasheet presents the material within the American (ASTM / ASME / UNS) standard system.
A second-generation member of the INCOLOY 900-series low-expansion alloys, Incoloy 907 has the low coefficient of thermal expansion and high strength of alloy 903 but with markedly improved notch-rupture properties at elevated temperature. Because aluminium was found to be detrimental to rupture properties, the aluminium content of alloy 907 is strictly controlled (below about 0.2%) and the resulting loss of precipitation hardening is offset by a higher niobium content, together with a silicon addition that further improves stress-rupture behaviour. Strengthening is by precipitation of γ′ / γ″ (Ni₃(Nb,Ti)) phases during ageing, while the nickel, cobalt and iron control the Curie temperature and low-expansion behaviour. It is used in the solution-treated and aged condition.
Typical applications include gas-turbine seals, shafts, casings, rings and other structural components requiring a low, constant coefficient of thermal expansion with high strength and good notch-rupture properties.
| 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) | 437 | J/kg·K |
| Structure | Austenitic (FCC) | — |
| Element | Symbol | Min % | Max % | Role in Alloy |
|---|---|---|---|---|
| Iron | Fe | Balance | — | Base element; low-expansion matrix |
| Nickel | Ni | 35.0 | 40.0 | Controls expansion / Curie temperature; γ′ matrix |
| Cobalt | Co | 13.0 | 16.0 | Controls expansion; raises inflection temperature |
| Niobium | Nb | 4.30 | 5.20 | γ′ / γ″ precipitation strengthening |
| Titanium | Ti | 1.20 | 1.80 | γ′ precipitation strengthening |
| Silicon | Si | 0.25 | 0.70 | Improves stress-rupture properties |
| Aluminium | Al | — | 0.20 | Controlled low (detrimental to rupture) |
| Carbon | C | — | 0.06 | Carbide formation |
Age-hardened condition, typical values for UNS N19907.
| Condition | Property | Value |
|---|---|---|
| Solution treated & aged | Tensile strength (UTS) | ≥1170 MPa (170 ksi) |
| Solution treated & aged | 0.2% yield strength | ≥965 MPa (140 ksi) |
| Solution treated & aged | Elongation at break | ≥13 % |
| Solution treated & aged | Reduction of area | ≥25 % |
| — | Elastic modulus | 159 GPa |
Confirm against the mill test report. Alloy 907 retains the low, constant coefficient of thermal expansion of alloy 903 while offering improved notch-rupture strength at elevated temperature.
| 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-rupture at temperature | Very Good | Improved over alloy 903 |
| Elevated-temperature strength | Excellent | Combined with low expansion |
The alloy is selected for its controlled expansion, high strength and improved notch-rupture properties 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′ / γ″ precipitation-hardenable controlled-expansion alloy; strengthened by solution treatment followed by ageing.
Solution Treatment Solution anneal at approximately 980 °C (1800 °F) for about 1 hour and air cool, or per the applicable specification for the product form.
Precipitation Hardening (Ageing) Age at approximately 775 °C (1425 °F) for a period, furnace cool, then hold near 620 °C (1150 °F) — precipitating γ′ / γ″ (Ni₃(Nb,Ti)). A single- or two-step age is selected to balance strength, notch-rupture properties and expansion behaviour.
Good weldability; welded by gas-tungsten-arc and gas-metal-arc processes in the solution-annealed condition with post-weld ageing. The aluminium restriction and silicon addition improve weld and rupture behaviour relative to alloy 903.
| Welding Process | Applicability | Filler / Consumable |
|---|---|---|
| GTAW / TIG | Good | Matching alloy 907 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-annealed for machining, then age |
| Machinability | Difficult; rigid setups, carbide tooling, slow speeds |
| Coolant | Ample coolant |
Forming Processes
| Process | Notes |
|---|---|
| Cold forming | Conventional techniques; heavy-duty lubricants required |
| Hot forming | Readily forged; solution and age afterward |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Aero gas turbine | Seals, shafts, casings, rings | Low expansion + notch-rupture strength |
| Propulsion | Structural and clearance-control parts | Dimensional stability |
| Power generation | High-temperature structural parts | Strength + low expansion |
| Aerospace | Constant-modulus / low-CTE hardware | Stability + strength |
| Product Form | Standard / Designation | Notes |
|---|---|---|
| Round bar and rod | UNS N19907 | Special Metals product |
| Billet and straight forgings | UNS N19907 | — |
| Welding wire | UNS N19907 | — |
| Material designation | UNS N19907 | Second-generation low-expansion alloy |
Nickel-iron-cobalt controlled-expansion alloy. UNS N19907.
| Alloy | Type | Al Control | Strengthening | Best Used For |
|---|---|---|---|---|
| Incoloy 907 | Ni-Fe-Co controlled expansion | Restricted (<0.2%) + Si | γ′ / γ″ (Nb, Ti) | Low expansion + improved notch-rupture; turbine seals, shafts |
| Incoloy 903 | Ni-Fe-Co controlled expansion | Al-bearing | γ′ / γ″ (Nb, Ti, Al) | First-generation low-expansion alloy |
| Incoloy 909 | Fe-Ni-Co controlled expansion | Restricted + high Si | γ′ (Nb, Ti) | Silicon-bearing low-expansion gas-turbine parts |
| Inconel 783 | Ni-Co-Fe + Al | Al-bearing | γ′ + β (NiAl) | Oxidation-resistant low-expansion alloy |
| Inconel 718 | Ni-Cr-Fe | — | γ′ + γ″ (Nb, Ti) | Most-used high-strength superalloy |
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