Alloy 22，Hastelloy C-22 Rod，UNS N06022

British Specs:，American Specs:，German Specs:WS 2.4602

Alloy 22 (Hastelloy C-22 Wire, UNS N06022) - Introduction with Composition, Properties, Applications and Product Forms

Alloy 22, commercially known as Hastelloy C-22 and designated by UNS N06022, is a premium nickel-chromium-molybdenum-tungsten superalloy celebrated for its exceptional resistance to a broad spectrum of corrosive environments, including both oxidizing 

and reducing conditions. This high-performance alloy combines superior corrosion resistance with excellent mechanical strength, high-temperature stability, and outstanding fabricability, making it a top choice for extreme industrial applications. It is available in a comprehensive range of forms to meet diverse needs, including Bar (Round bar, Flat bar), Ribbon, Wire, Rods, Tube, Pipe, Foil, Plate, Sheet, Strip, and Forging Stock. Hastelloy C-22 Wire, in particular, is valued for its flexibility, precision, and consistent performance, making it ideal for intricate components in chemical processing, aerospace, and marine industries. Below is a detailed overview of its chemical composition, key properties, practical applications, and available product forms.

Chemical Composition

The precisely engineered chemical composition of Alloy 22 (Hastelloy C-22, UNS N06022) is the foundation of its exceptional corrosion resistance and mechanical performance. The typical composition (by weight) is as follows:

Nickel (Ni): 50-60% (primary matrix element, providing a stable base for corrosion resistance and structural integrity)

Chromium (Cr): 20-22% (critical for oxidation resistance, forming a protective chromium oxide layer in oxidizing environments)

Molybdenum (Mo): 12-14% (enhances resistance to reducing acids, pitting, and crevice corrosion in aggressive environments)

Tungsten (W): 2.5-3.5% (boosts resistance to pitting and crevice corrosion, particularly in chloride-rich solutions)

Iron (Fe): 2.0-6.0% (improves fabricability and mechanical stability at ambient and elevated temperatures)

Cobalt (Co): ≤ 2.5% (aids in solid solution strengthening and thermal stability)

Manganese (Mn): ≤ 0.5% (assists in deoxidation during manufacturing and improves weldability)

Silicon (Si): ≤ 0.08% (minimized to prevent the formation of brittle phases, preserving ductility)

Carbon (C): ≤ 0.015% (strictly controlled to avoid carbide precipitation, which could reduce corrosion resistance)

Sulfur (S): ≤ 0.02% (kept at very low levels to ensure good ductility and weldability)

Phosphorus (P): ≤ 0.03% (controlled to maintain corrosion resistance and avoid embrittlement)

This balanced composition synergistically delivers the alloy's signature broad-spectrum corrosion resistance, high-temperature strength, and formability, making it suitable for the most demanding industrial environments.

Key Properties

Alloy 22 (Hastelloy C-22 Wire, UNS N06022) and its various forms exhibit a robust set of properties that make them indispensable in corrosive, high-temperature, and high-stress applications:

Mechanical Properties (room temperature, annealed condition):

Tensile strength: 690-860 MPa (100,000-124,700 psi)

Yield strength (0.2% offset): 280-410 MPa (40,600-59,500 psi)

Elongation (in 50 mm): 40-50% (excellent ductility, enabling complex forming, bending, and welding across all product forms)

Hardness: 190-230 HB (Brinell hardness, indicating good machinability and wear resistance)

High-Temperature Performance:

Thermal stability: Maintains significant strength up to 1000°C (1832°F), with tensile strength remaining above 350 MPa at 700°C (1292°F)

Creep resistance: Exhibits excellent creep resistance at 600-800°C (1112-1472°F), suitable for long-term service under sustained stress in high-temperature systems

Oxidation resistance: Resistant to oxidation in air and combustion gases up to 1095°C (2003°F), forming a dense, self-healing chromium oxide layer

Thermal fatigue resistance: Superior resistance to thermal cycling, making it ideal for applications with frequent temperature fluctuations

Corrosion Resistance:

Broad-spectrum resistance: Exceptional resistance to both oxidizing acids (e.g., nitric acid, chromic acid) and reducing acids (e.g., hydrochloric acid, sulfuric acid), a key advantage over more specialized alloys

Chloride resistance: Outstanding resistance to pitting and crevice corrosion in chloride-rich environments, including seawater, brines, and industrial effluents, with a high Critical Pitting Temperature (CPT) exceeding 40°C (104°F)

Wet corrosion: Resistant to alkaline solutions, organic acids, and industrial chemicals, ensuring versatility across diverse industries

Stress corrosion cracking (SCC): Highly resistant to SCC in chloride-containing environments, even at elevated temperatures and high stress levels

Physical Properties:

Density: 8.6 g/cm³ (0.310 lb/in³)

Thermal conductivity: 10.8 W/(m·K) at 20°C (68°F), increasing to 19.0 W/(m·K) at 1000°C (1832°F)

Melting point: 1325-1370°C (2417-2498°F)

Coefficient of thermal expansion: 12.3 μm/(m·K) (20-100°C), rising to 17.1 μm/(m·K) at 1000°C (1832°F)

Modulus of elasticity: 205 GPa (29,700 ksi) at room temperature, decreasing to 160 GPa (23,200 ksi) at 1000°C (1832°F)

Product Forms

Alloy 22 (Hastelloy C-22, UNS N06022) is manufactured in a diverse range of forms to accommodate specialized industrial processes across chemical, aerospace, marine, and nuclear sectors:

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), ideal for machining into valve components, pump shafts, 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, gaskets, and seals for corrosive equipment.

Wire: Hastelloy C-22 Wire (diameters 0.05 mm to 10 mm) offers excellent flexibility and corrosion resistance, making it suitable for thermocouple leads, sensor wiring, woven mesh filters, and precision springs in aggressive environments.

Rods: Solid cylindrical rods (diameters 3 mm to 50 mm) suitable for structural supports in chemical reactors, aerospace components, and high-temperature machinery.

Tube and Pipe: Seamless and welded options (outer diameter 6 mm to 200 mm, wall thickness 0.5 mm to 20 mm) for transporting corrosive fluids, including acids and industrial chemicals, in processing systems.

Foil: Ultra-thin sheets (thickness 0.01 mm to 0.1 mm) used in lightweight corrosion barriers, thermal insulation, and precision electronic components.

Plate and Sheet: Flat forms (plate: thickness 5 mm to 100 mm; sheet: 0.3 mm to 5 mm) for fabricating reactor vessel liners, storage tanks, heat exchanger panels, and aerospace structural parts.

Strip: Narrow, flat strips (thickness 0.1 mm to 3 mm, width 10 mm to 200 mm) for precision manufacturing in gaskets, clips, and electrical components for corrosive systems.

Forging Stock: Billets and ingots for hot forging into complex shapes such as pump impellers, valve bodies, and aerospace engine components.

Applications

The exceptional properties of Alloy 22 (Hastelloy C-22 Wire, UNS N06022) across its various forms make it a critical material in industries requiring resistance to the most aggressive corrosive environments and high temperatures:

Chemical Processing:

Acid production and handling: Tanks, pipes, and valves (from plate, tube, and bar) for processing and transporting both oxidizing and reducing acids, including sulfuric acid, nitric acid, and hydrochloric acid.

Pharmaceutical manufacturing: Equipment for producing high-purity chemicals, including reaction vessels (from plate) and transfer lines (from tube), ensuring product purity and corrosion resistance.

Pulp and paper industry: Components exposed to chlorinated acids and bleaching agents, such as digester liners (from plate) and washers (from sheet).

Aerospace and Aviation:

Gas turbine engines: Combustion chamber components (from sheet and plate), turbine blade retainers (from forging stock), and heat shields (from foil) leveraging high-temperature stability and oxidation resistance.

Rocket propulsion systems: Components exposed to high-temperature exhaust gases and corrosive propellants, such as nozzles (from forging stock) and fuel lines (from tube).

Aerospace instrumentation: Precision components (from wire and strip) for sensors and control systems, resisting corrosion from hydraulic fluids and atmospheric exposure.

Marine and Offshore:

Offshore oil and gas platforms: Piping systems (from tube) for seawater injection, processing equipment (from plate), and structural supports (from rod) exposed to salt spray and brines.

Desalination plants: Heat exchanger tubes (from tube) and pressure vessels (from plate) for seawater desalination, withstanding chloride-induced pitting.

Marine engineering: Hull components, propeller shafts, and seawater intake systems (from plate, sheet, and bar) resisting seawater corrosion.

Nuclear Industry:

Nuclear waste processing: Containment vessels (from plate) and transfer lines (from tube) for handling radioactive waste, ensuring corrosion resistance and structural integrity.

Nuclear power plants: Heat exchanger components (from tube and sheet) and reactor internals (from forging stock) resisting corrosive coolants and high temperatures.

Specialized Applications by Form:

Wire: Thermocouple leads in high-temperature furnaces, sensor wiring in chemical reactors, and woven filters for acid filtration.

Tube/Pipe: Chemical transport lines, heat exchanger tubes in power plants, and sampling lines for aggressive fluids.

Plate/Sheet: Reactor vessel liners, storage tank walls, and aerospace structural panels resistant to both corrosion and high temperatures.

Bar/Rod: Machined valves, pump shafts, and fasteners for the most corrosive environments where strength and reliability are critical.

In summary, Alloy 22 (Hastelloy C-22 Wire, UNS N06022) — available in forms from Bar and Wire to Plate and Forging Stock — delivers exceptional broad-spectrum corrosion resistance, high-temperature stability, and formability. Its diverse product forms enable tailored solutions across chemical processing, aerospace, marine, and nuclear sectors, establishing it as a critical material in the most demanding industrial 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 2730 gallon liquid totes Special package is available on request.