Alloy 75,Haynes 75 Other/Similar Specs,UNS N06075

Alloy 75,Haynes 75 Wire,UNS N06075

Alloy 75 (Haynes 75 Wire, UNS N06075) - Introduction with Composition, Properties, Applications and Product Forms

Alloy 75, commercially known as Haynes 75 and designated by UNS N06075, is a high-performance nickel-chromium-cobalt superalloy renowned for its exceptional high-temperature strength, creep resistance, and long-term oxidation stability. This alloy is specifically engineered to excel in extreme thermal environments—including prolonged exposure to elevated temperatures, cyclic mechanical stress, and harsh atmospheres like combustion gases—making it a critical material in aerospace, energy, and industrial sectors where components must withstand extreme heat and heavy operational loads. 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. Haynes 75 Wire, in particular, stands out for its uniform high-temperature properties, flexibility, and precision, making it ideal for welding, thermal spray coatings, and intricate components in gas turbine hot sections and high-heat industrial systems. 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 75 (Haynes 75 Wire, UNS N06075) is the foundation of its exceptional high-temperature performance and corrosion resistance. The typical composition (by weight) is as follows:

Nickel (Ni): 73-77% (the primary matrix element, delivering structural stability at ultra-high temperatures and serving as the base for strength-enhancing precipitates)

Chromium (Cr): 15-17% (forms a dense, adherent chromium oxide layer, ensuring superior oxidation and sulfidation resistance at temperatures up to 1050°C)

Cobalt (Co): 6-8% (enhances high-temperature strength, creep resistance, and thermal fatigue performance by stabilizing the alloy matrix and reducing precipitate coarsening)

Iron (Fe): ≤ 0.5% (minimized to preserve high-temperature properties and prevent degradation of oxidation resistance)

Manganese (Mn): 0.5-1.0% (enhances hot workability, enabling fabrication into diverse product forms like wire, foil, and strip, while aiding in desulfurization)

Silicon (Si): 0.2-0.5% (aids in deoxidation during manufacturing and supports the formation of a stable oxide layer for enhanced long-term oxidation resistance)

Carbon (C): 0.05-0.10% (forms fine carbides with chromium, reinforcing grain boundaries and improving creep resistance without compromising ductility)

Copper (Cu): ≤ 0.3% (strictly limited to avoid reducing the alloy’s high-temperature strength and corrosion resistance)

Sulfur (S): ≤ 0.01% (minimized to ensure good ductility and resistance to stress corrosion cracking in harsh environments)

Phosphorus (P): ≤ 0.015% (strictly limited to avoid grain boundary embrittlement under high stress or thermal cycling)

This engineered blend—focused on nickel, chromium, and cobalt—delivers Alloy 75’s signature balance of high-temperature strength, creep resistance, and oxidation stability, critical for demanding thermal applications.

Key Properties

Alloy 75 (Haynes 75 Wire, UNS N06075) and its various forms exhibit exceptional properties that make them indispensable in ultra-high-temperature, corrosive, and cyclic-stress environments:

Mechanical Properties (solution-annealed and aged condition):

Tensile strength: 950-1100 MPa (137,800-159,500 psi) at room temperature; retains ~400 MPa (58,000 psi) at 850°C (1562°F)

Yield strength (0.2% offset): 650-750 MPa (94,300-108,800 psi) at room temperature; retains ~350 MPa (50,800 psi) at 850°C (1562°F)

Elongation (in 50 mm): 22-32% at room temperature; 15-23% at 850°C (1562°F) (excellent ductility for forming complex components like turbine seals and combustion liners)

Reduction of area: 40-50% (superior toughness, resisting fracture under high-temperature cyclic stress and mechanical impact)

Hardness: 32-37 HRC (Rockwell hardness) at room temperature; maintains ~22 HRC at 850°C (1562°F)

High-Temperature Properties:

Continuous service temperature: Up to 920°C (1688°F) (a top performer for nickel-chromium-cobalt alloys, with long-term stability in air and industrial combustion atmospheres)

Creep resistance: Exceptional resistance to creep deformation—1000-hour creep rupture strength of ~190 MPa (27,560 psi) at 850°C (1562°F) and ~95 MPa (13,780 psi) at 920°C (1688°F)

Thermal fatigue resistance: Withstands repeated thermal cycling (e.g., 120°C to 880°C) without cracking, critical for components like gas turbine combustion liners and exhaust manifolds

Oxidation resistance: Superior resistance to oxidation and scaling in air at temperatures up to 1050°C (1922°F), with minimal weight gain (≤ 4 mg/cm²) even after 5000 hours at 920°C (1688°F)

Corrosion Resistance:

General corrosion: Excellent resistance to high-temperature combustion gases (including jet fuel and natural gas byproducts), industrial steam, and mild organic/inorganic chemicals

Sulfidation resistance: Resists sulfidation in sulfur-containing environments (e.g., coal-fired power plants, waste incinerators) up to 850°C (1562°F)

Pitting/crevice corrosion: Good resistance to pitting in mild chloride environments (e.g., aerospace components exposed to marine atmospheres and humidity)

Carburization resistance: Maintains integrity in mild carburizing atmospheres (e.g., industrial heat-treating furnaces) by limiting carbon absorption and preventing excessive carbide growth

Physical Properties:

Density: 7.8-8.0 g/cm³ (0.282-0.289 lb/in³)

Thermal conductivity: 10.0-12.0 W/(m·K) at 20°C (68°F); increases to 20-23 W/(m·K) at 900°C (1652°F) (efficient heat dissipation at high temperatures, reducing thermal stress in components)

Coefficient of thermal expansion: 12.0-14.0 μm/(m·K) (20-900°C) (controlled expansion to minimize thermal stress in assembled systems like turbine casings)

Modulus of elasticity: 190-200 GPa (27,500-28,900 ksi) at room temperature; decreases to ~130 GPa (18,850 ksi) at 900°C (1652°F)

Melting point: 1330-1380°C (2426-2516°F)

Product Forms

Alloy 75 (Haynes 75 Wire, UNS N06075) is manufactured in a diverse range of forms to accommodate specialized high-temperature and corrosion-resistant applications:

Bar: Available as Round bar (diameters from 6 mm to 160 mm) and Flat bar (thickness 3 mm to 80 mm, width 12 mm to 400 mm), ideal for machining into turbine components, valve stems, and high-temperature fasteners.

Ribbon: Thin, flat strips (thickness 0.07 mm to 0.8 mm, width 3 mm to 80 mm) used in thermal spray coatings, high-temperature electrical heating elements, and flexible seals for industrial furnaces.

Wire: Haynes 75 Wire (diameters 0.3 mm to 4.5 mm) offers uniform high-temperature properties, suitable for welding (TIG/MIG), thermal spray applications, and precision heating coils in high-heat industrial systems.

Rods: Solid cylindrical rods (diameters 1.5 mm to 40 mm) used for gas tungsten arc welding (GTAW) filler metal and manufacturing small high-temperature components (e.g., sensor supports, valve pins).

Tube and Pipe: Hollow forms (outer diameter 4 mm to 80 mm, wall thickness 0.3 mm to 8 mm) for high-temperature fluid transport (e.g., gas turbine fuel lines, heat exchanger tubes in power plants).

Foil: Ultra-thin sheets (thickness 0.012 mm to 0.08 mm) used in high-temperature gaskets, heat shields for aerospace electronics, and thin-film thermal barriers.

Plate and Sheet: Flat forms (plate: thickness 1.5 mm to 40 mm; sheet: 0.2 mm to 1.5 mm) for fabricating combustion liners, furnace walls, and aerospace heat exchangers.

Strip: Narrow, flat strips (thickness 0.07 mm to 1.6 mm, width 1.5 mm to 40 mm) for precision components like turbine seals, heat exchanger fins, and electrical contacts in high-temperature environments.

Forging Stock: Billets and ingots for hot forging into complex shapes (e.g., gas turbine disks, compressor blades, industrial furnace doors) requiring exceptional high-temperature strength.

Applications

The exceptional high-temperature strength, creep resistance, and oxidation stability of Alloy 75 (Haynes 75 Wire, UNS N06075) across its various forms make it a critical material in industries requiring performance under extreme thermal conditions:

Aerospace and Aviation:

Gas turbine engines: Compressor blades, turbine vanes, combustion liners, and afterburner components (from plate, forging stock, and sheet) withstanding temperatures up to 920°C (1688°F).

Aerospace fasteners: High-temperature bolts, studs, and rivets (from bar and rod) securing engine hot-section components exposed to cyclic thermal stress and vibration.

Auxiliary power units (APUs): Heat exchanger tubes and structural parts (from tube and sheet) resisting high temperatures in aircraft auxiliary systems.

Energy and Power Generation:

Gas/steam turbines: Hot-section components (from plate, forging stock, and bar) for industrial power turbines, enduring high temperatures and cyclic loading.

Waste-to-energy plants: Combustion chamber liners and heat recovery components (from sheet and plate) withstanding corrosive flue gases and temperatures above 850°C.

Nuclear power: Heat exchanger tubes and structural components (from tube and plate) resisting radiation and high-temperature coolants.

Industrial and High-Temperature Processing:

High-temperature furnaces: Furnace walls, heating elements, thermocouple sheaths, and hearth plates (from wire, plate, and tube) operating in air or inert atmospheres up to 1050°C (1922°F).

Chemical processing: Reactor liners, catalyst support grids, and heat exchangers (from plate, tube, and bar) withstanding mild aggressive chemicals (e.g., weak acids, organic solvents) at elevated temperatures.

Metallurgical processing: Heat treatment fixtures, molten metal handling parts, and annealing furnace components (from bar, forging stock, and plate) resisting wear and high heat.

Defense and Specialized Engineering:

Military aircraft engines: Critical hot-section components (from forging stock and plate) requiring high-temperature durability in combat environments.

Missile propulsion systems: Combustion chamber liners and exhaust components (from sheet and forging stock) resisting extreme heat from propellant combustion.

Naval systems: Marine gas turbine components (from plate, tube, and bar) resisting seawater corrosion and high temperatures.

Specialized Applications by Form:

Wire: Welding filler metal for joining high-temperature components, thermal spray coatings for wear and corrosion protection, and precision heating coils.

Plate/Sheet: Combustion liners, furnace walls, and aerospace heat exchangers requiring large, flat high-temperature surfaces.

Tube/Pipe: High-temperature fluid transport (fuel lines, heat exchanger tubes) and thermocouple protection sheaths in corrosive environments.

Forging Stock: Complex turbine disks, compressor blades, and heavy-duty industrial furnace components requiring custom shapes and exceptional high-temperature strength.

In summary, Alloy 75 (Haynes 75 Wire, UNS N06075) — available in forms from Bar and Wire to Plate and Forging Stock — delivers exceptional high-temperature strength, creep resistance, and oxidation stability. Its diverse product forms enable tailored solutions across aerospace, energy, industrial, and defense sectors, establishing it as a critical material in applications requiring reliable performance under extreme thermal conditions.

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 1088 gallon liquid totes Special package is available on request.