Alloy 909,Incoloy 909 Foil，Shim,UNS N19909

Alloy 909,Incoloy 909 Wire,UNS N19909

Alloy 909 (Incoloy 909 Wire, UNS N19909) - Introduction with Composition, Properties, Applications and Product Forms

Alloy 909, commercially known as Incoloy 909 and designated by UNS N19909, is a precipitation-hardening nickel-iron-cobalt superalloy uniquely engineered for low thermal expansion and exceptional high-temperature strength. Unlike traditional corrosion-focused superalloys, it is optimized for applications requiring dimensional stability under extreme thermal cycling—from cryogenic temperatures to elevated heat—making it a critical material in aerospace, defense, and advanced energy sectors. It is available in a comprehensive range of forms to meet diverse industrial needs, including Bar (Round bar, Flat bar), Ribbon, Wire, Rods, Tube, Pipe, Foil, Plate, Sheet, Strip, and Forging Stock. Incoloy 909 Wire, in particular, stands out for its uniform low thermal expansion and precision, making it ideal for welding, spring manufacturing, and intricate components in rocket engines and satellite structures. Below is a detailed overview of its chemical composition, key properties, practical applications, and available product forms.

Chemical Composition

The precisely balanced chemical composition of Alloy 909 (Incoloy 909, UNS N19909) is the foundation of its ultra-low thermal expansion and high-temperature strength. The typical composition (by weight) is as follows:

Nickel (Ni): 38-42% (the primary matrix element, enabling precipitation of strengthening phases and providing baseline ductility; also enhances low-temperature toughness)

Iron (Fe): 34-38% (balances the alloy’s density and cost while working with nickel-cobalt to suppress thermal expansion; improves fabricability for wire and sheet forming)

Cobalt (Co): 18-22% (the key contributor to ultra-low thermal expansion—forms a "thermally compensated" matrix with nickel and iron, minimizing dimensional changes under temperature fluctuations)

Niobium (Nb) + Titanium (Ti): 4.5-5.5% (combined; Nb: 3.0-4.0%, Ti: 1.5-2.0%) — form gamma-double-prime (γ'') intermetallic precipitates during aging, delivering exceptional high-temperature strength without increasing thermal expansion

Aluminum (Al): 0.1-0.5% (refines γ'' precipitates, enhancing strength at elevated temperatures while preserving ductility)

Carbon (C): ≤ 0.03% (minimized to prevent carbide formation, which could increase thermal expansion and cause grain boundary embrittlement)

Silicon (Si): ≤ 0.3% (aids in deoxidation during manufacturing without compromising low thermal expansion properties)

Manganese (Mn): ≤ 0.5% (enhances hot workability, enabling fabrication into thin forms like wire and foil)

Phosphorus (P): ≤ 0.015% (strictly limited to avoid grain boundary embrittlement, critical for cryogenic and high-stress applications)

Sulfur (S): ≤ 0.01% (minimized to ensure good ductility and resistance to stress corrosion cracking under thermal cycling)

Boron (B): 0.002-0.008% (strengthens grain boundaries, improving creep resistance at high temperatures without altering thermal expansion)

This engineered blend—focused on nickel-iron-cobalt for low thermal expansion and niobium-titanium for strength—delivers Alloy 909’s unique "dimensional stability + high strength" performance.

Key Properties

Alloy 909 (Incoloy 909 Wire, UNS N19909) and its various forms exhibit exceptional properties tailored for thermal cycling and high-stress environments:

Mechanical Properties (Aged Condition, 705°C/1300°F for 8 hours + 620°C/1150°F for 8 hours)

Tensile Strength: 1240-1450 MPa (180,000-210,000 psi) at room temperature; retains ~965 MPa (140,000 psi) at 650°C (1200°F)

Yield Strength (0.2% offset): 1035-1240 MPa (150,000-180,000 psi) at room temperature; retains ~895 MPa (130,000 psi) at 650°C (1200°F)

Elongation (in 50 mm): 12-20% (excellent ductility for cold forming—e.g., bending wire into precision springs, shaping sheet into satellite components)

Reduction of Area: 25-35% (superior toughness, resisting fracture under thermal cycling and mechanical stress)

Hardness: 38-44 HRC (Rockwell hardness) at room temperature; maintains ~32 HRC at 650°C (1200°F)

Thermal Expansion (Core Advantage)

Coefficient of Thermal Expansion (CTE): Ultra-low and stable across a wide temperature range:

20-300°C (68-572°F): 4.0-5.5 μm/(m·K) (1/3 of 316 stainless steel; 1/2 of Incoloy 925)

20-650°C (68-1200°F): 5.5-7.0 μm/(m·K) (minimal increase even at elevated temperatures, ensuring dimensional stability)

Cryogenic (-270°C/-454°F to 20°C/68°F): CTE remains near-zero, avoiding brittle fracture in low-temperature applications

High-Temperature Properties

Continuous Service Temperature: Up to 700°C (1292°F) (maintains strength and low thermal expansion; short-term exposure up to 800°C/1472°F)

Creep Resistance: Exceptional for a low-CTE alloy—1000-hour creep rupture strength of ~480 MPa (70,000 psi) at 650°C (1200°F) (outperforms most low-expansion steels)

Thermal Fatigue Resistance: Withstands 10,000+ thermal cycles (e.g., -196°C/-321°F to 650°C/1200°F) without cracking, critical for rocket engines and turbine components

Low-Temperature & Corrosion Properties

Cryogenic Toughness: Retains ductility at -270°C (-454°F) (no brittle transition, suitable for LNG and space applications)

General Corrosion: Moderate resistance to atmospheric moisture, industrial steam, and mild acids (focused on thermal performance over extreme corrosion resistance; supplementary coatings used for harsh chemical environments)

Physical Properties

Density: 8.2 g/cm³ (0.296 lb/in³) (higher than low-expansion steels but balanced by superior strength)

Thermal Conductivity: 11.5 W/(m·K) at 20°C (68°F); increases to 18.5 W/(m·K) at 650°C (1200°F) (controlled heat transfer for thermal management components)

Modulus of Elasticity: 210 GPa (30,500 ksi) at room temperature; decreases to ~180 GPa (26,100 ksi) at 650°C (1200°F)

Melting Point: 1340-1390°C (2444-2534°F)

Product Forms

Alloy 909 (Incoloy 909, UNS N19909) is manufactured in a diverse range of forms to accommodate specialized thermal cycling and high-stress applications:

Bar: Round bar (diameters 8-200 mm) and Flat bar (thickness 6-100 mm, width 25-500 mm) — ideal for machining into rocket engine nozzles, turbine disks, and high-precision fasteners.

Ribbon: Thin, flat strips (thickness 0.08-0.9 mm, width 4-90 mm) — used in thermal spray coatings for dimensional stability on metal substrates and flexible seals for high-temperature chambers.

Wire: Incoloy 909 Wire (diameters 0.4-6 mm) — serves as welding filler metal for joining 909 components, as precision springs in satellite deployment mechanisms, and as sensor wires in cryogenic systems.

Rods: Solid cylindrical rods (diameters 3-50 mm) — used for GTAW filler metal and manufacturing small components like valve stems and instrument probes in thermal-cycling environments.

Tube and Pipe: Seamless tube (outer diameter 5-150 mm, wall thickness 0.6-10 mm) — critical for high-temperature fluid transport (e.g., rocket fuel lines, turbine cooling tubes) requiring dimensional stability.

Foil: Ultra-thin sheets (thickness 0.015-0.1 mm) — used as thermal barriers in electronic components and thin gaskets in precision instruments exposed to temperature fluctuations.

Plate and Sheet: Plate (thickness 4-50 mm) and Sheet (thickness 0.3-4 mm) — fabricated into satellite structural panels, rocket engine combustion liners, and turbine heat shields.

Strip: Narrow, flat strips (thickness 0.08-2 mm, width 3-50 mm) — used for precision components like heat exchanger fins, electrical contacts, and seal rings in thermal-cycling systems.

Forging Stock: Billets and ingots (sizes up to 600×600 mm) — hot-forged into complex shapes (e.g., turbine rotors, rocket engine casings) requiring low thermal expansion and high strength.

Applications

The exceptional low thermal expansion and high-temperature strength of Alloy 909 (Incoloy 909 Wire, UNS N19909) make it irreplaceable in industries where dimensional stability under thermal cycling is critical:

Aerospace & Defense

Rocket & Missile Engines: Combustion liners (plate/sheet), nozzles (bar/forging stock), and fuel lines (tube) — withstands extreme thermal cycling (cryogenic propellants to 1000°C+ exhaust) without warping.

Satellites & Spacecraft: Structural panels (sheet), deployment springs (wire), and antenna supports (rod) — maintains dimensional precision in space’s extreme temperature swings (-270°C to 120°C).

Jet Engines: High-pressure turbine components (forging stock/plate) — resists thermal fatigue from engine start-stop cycles and retains strength at 650-700°C.

Advanced Energy

Nuclear Fusion: Plasma-facing components (plate) — withstands thermal cycling between cryogenic cooling and 600°C plasma exposure while maintaining shape.

LNG Industry: Cryogenic storage tank liners (sheet/foil) and transfer pipes (tube) — retains ductility at -162°C (LNG boiling point) and minimizes expansion/contraction during filling/emptying.

Turbine Technology: Heat exchanger tubes (tube) and rotor disks (forging stock) — ensures dimensional stability in combined-cycle gas turbines (CCGT) with frequent temperature changes.

Precision Engineering

Semiconductor Manufacturing: Wafer processing equipment (plate/strip) — maintains precision in high-temperature annealing chambers with tight dimensional tolerances.

Metrology Tools: Calibration standards (bar) — ultra-low CTE ensures accuracy across temperature ranges in industrial measurement systems.

Specialized Applications by Form

Wire: Welding filler metal for rocket engine components; precision springs in satellite deployment mechanisms.

Plate/Sheet: Satellite structural panels and rocket engine combustion liners.

Tube/Forging Stock: Rocket fuel lines and turbine rotors requiring dimensional stability.

Strip/Foil: Thermal barriers in electronics and cryogenic gaskets.

In summary, Alloy 909 (Incoloy 909 Wire, UNS N19909) — available in forms from Bar and Wire to Plate and Forging Stock — redefines performance for thermal-cycling applications. Its unique low thermal expansion and high strength enable innovations in aerospace, space, and energy sectors, where traditional materials fail to maintain dimensional stability. It is the material of choice for engineers seeking to eliminate thermal-induced failure and ensure long-term precision.

Packing of Standard Packing:

Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and steel drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 1019 gallon liquid totes Special package is available on request.