Alloy 702，Inconel 702 Tube，UNS N07702

British Specs:，American Specs: AMS 5550 Sheet, Strip and Plate，German Specs:

Alloy 702 and Inconel 702 Wire (UNS N07702) - Introduction with Composition, Properties, Applications and Product Forms

Alloy 702, commercially designated as Inconel 702 with the UNS number N07702, is a nickel-chromium-based superalloy renowned for its exceptional high-temperature oxidation resistance, good mechanical strength, and excellent fabricability. This versatile material is available in an extensive range of forms to suit diverse industrial needs, including Bar (Round bar, Flat bar), Ribbon, Wire, Rods, Tube, Pipe, Foil, Plate, Sheet, Strip, and Forging Stock. Inconel 702 Wire, in particular, offers unique flexibility for intricate high-temperature applications. Below is a detailed overview of its chemical composition, key properties, practical applications, and available product forms.

Chemical Composition

The carefully balanced chemical composition of Alloy 702 (Inconel 702, UNS N07702) is pivotal to its outstanding performance in high-temperature environments. The typical composition (by weight) is as follows:

Nickel (Ni): 72-76% (primary matrix element, providing the base for high-temperature stability and corrosion resistance)

Chromium (Cr): 14-17% (a key element for oxidation resistance, forming a protective chromium oxide layer at elevated temperatures)

Iron (Fe): 5.0-9.0% (enhances mechanical strength and balances the alloy structure)

Manganese (Mn): ≤ 1.0% (aids in deoxidation during manufacturing and improves fabricability)

Silicon (Si): 0.5-1.0% (promotes the formation of a stable oxide layer, enhancing oxidation resistance)

Carbon (C): ≤ 0.10% (controls carbide formation to maintain ductility and prevent grain boundary embrittlement)

Copper (Cu): ≤ 0.50% (trace element, with minimal impact on overall properties)

Sulfur (S): ≤ 0.015% (kept low to ensure good weldability and reduce the risk of hot cracking)

Phosphorus (P): ≤ 0.02% (controlled to maintain grain boundary strength)

This composition works synergistically to provide the alloy with its signature combination of oxidation resistance and mechanical integrity at high temperatures.

Key Properties

Alloy 702 and its various forms, including Inconel 702 Wire (UNS N07702), exhibit a robust set of properties that make them ideal for high-temperature applications:

Mechanical Properties (room temperature, annealed condition):

Tensile strength: 650-800 MPa (94,300-116,000 psi)

Yield strength (0.2% offset): 275-350 MPa (39,900-50,800 psi)

Elongation (in 50 mm): 30-40% (excellent ductility, enabling easy forming and welding)

Hardness: 150-200 HB (Brinell hardness, indicating good machinability)

High-Temperature Performance:

Thermal stability: Maintains useful strength up to 1000°C (1832°F), with tensile strength remaining above 200 MPa at 900°C (1652°F)

Oxidation resistance: Exceptional resistance to oxidation in air and combustion gases up to 1100°C (2012°F), forming a dense, adherent oxide layer that self-heals when damaged

Creep resistance: Moderate creep resistance at temperatures up to 800°C (1472°F), suitable for applications with moderate sustained stress

Corrosion Resistance:

Excellent resistance to high-temperature oxidation and sulfidation, making it ideal for furnace environments and combustion systems

Good resistance to aqueous corrosion in mild environments, including freshwater and some industrial chemicals

Resists chloride-induced stress corrosion cracking in low-chloride environments

Physical Properties:

Density: 8.3 g/cm³ (0.300 lb/in³)

Thermal conductivity: 15 W/(m·K) at 20°C (68°F), increasing to 25 W/(m·K) at 1000°C (1832°F)

Melting point: 1390-1430°C (2534-2594°F)

Coefficient of thermal expansion: 13.0 μm/(m·K) (20-100°C), increasing to 18.0 μm/(m·K) at 1000°C (1832°F)

Modulus of elasticity: 210 GPa (30,500 ksi) at room temperature, decreasing to 160 GPa (23,200 ksi) at 1000°C (1832°F)

Product Forms

Alloy 702 (UNS N07702) is manufactured in a wide range of forms to accommodate diverse industrial processes and applications:

Bar: Available as Round bar (diameters from 8 mm to 300 mm) and Flat bar (thickness 6 mm to 150 mm, width 20 mm to 600 mm), suitable for machining into furnace components and high-temperature fasteners.

Ribbon: Thin, flat strips (thickness 0.1 mm to 2 mm, width 5 mm to 100 mm) used in electrical heating elements and thermal insulation wraps.

Wire: Inconel 702 Wire (diameters 0.05 mm to 10 mm) offers excellent flexibility for forming heating coils, thermocouple leads, and woven mesh for high-temperature filtration.

Rods: Solid cylindrical rods (diameters 3 mm to 50 mm) ideal for structural supports and small-scale high-temperature components.

Tube and Pipe: Seamless and welded options (outer diameter 6 mm to 200 mm, wall thickness 0.5 mm to 20 mm) for high-temperature fluid transport in industrial furnaces and chemical processing.

Foil: Ultra-thin sheets (thickness 0.01 mm to 0.1 mm) used in lightweight thermal barriers and precision electronics.

Plate and Sheet: Flat forms (plate: thickness 5 mm to 100 mm; sheet: 0.3 mm to 5 mm) for fabricating furnace liners, heat shields, and aerospace components.

Strip: Narrow, flat strips (thickness 0.1 mm to 3 mm, width 10 mm to 200 mm) for precision manufacturing in high-temperature machinery.

Forging Stock: Billets and ingots for hot forging into complex shapes such as furnace hardware and aerospace engine parts.

Applications

The exceptional properties of Alloy 702 (Inconel 702 Wire, UNS N07702) across its various forms make it a preferred material in industries requiring reliable performance at high temperatures:

Industrial Furnaces and Heat Treatment:

Furnace components: Plates and sheets for furnace liners, retorts, and muffle boxes; bars for hearth rails and support brackets—all leveraging superior oxidation resistance.

Heating elements: Ribbon and wire formed into resistance heating coils for electric furnaces, operating at temperatures up to 1000°C (1832°F).

Thermal insulation: Foil and strip used in multi-layer insulation systems for high-temperature equipment.

Aerospace and Aviation:

Engine components: Sheets and plates for exhaust system heat shields; tubes for coolant lines in jet engines.

Spacecraft systems: Wire for thermocouple leads; foil for thermal management in re-entry vehicles, resisting extreme temperature fluctuations.

Chemical and Petrochemical Processing:

Reactor components: Tubes and pipes for high-temperature catalytic reactors; plates for reactor internals, resisting sulfidation and oxidation.

Filtration systems: Woven wire mesh (from wire form) for high-temperature gas and liquid filtration in chemical processes.

Power Generation:

Gas turbine systems: Sheets for combustion chamber liners; rods for structural supports in high-heat zones.

Waste incineration: Plates and tubes for incinerator liners, withstanding corrosive and high-temperature environments.

Specialized Applications by Form:

Wire: Thermocouple extension wires, heating coils, and braided hoses for high-temperature fluid transfer.

Tube/Pipe: High-temperature steam lines, process piping in chemical plants, and heat exchanger tubes.

Plate/Sheet: Furnace doors, heat shields, and radiation barriers in industrial and aerospace systems.

Bar/Rod: Machined parts like fasteners, spacers, and tooling for high-temperature forming processes.

In summary, Alloy 702 (Inconel 702 Wire, UNS N07702) — available in forms ranging from Bar and Wire to Plate and Forging Stock — delivers exceptional high-temperature oxidation resistance, good mechanical strength, and versatility. Its diverse product forms enable tailored solutions across industrial furnace, aerospace, and chemical processing sectors, making it a critical material in high-performance engineering applications.

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 2980 gallon liquid totes Special package is available on request.