Alloy 333，RA-33 Sheet，UNS N06333

British Specs:，American Specs: AMS 5717 Bar and Forgings AMS 5593 Sheet, Strip and Plate，German Specs:

Alloy 333 (RA-33 Wire, UNS N06333) - Introduction with Composition, Properties, Applications and Product Forms

Alloy 333, commercially known as RA-33 with the UNS designation N06333, is a nickel-chromium-molybdenum superalloy engineered for exceptional corrosion resistance in both oxidizing and reducing environments, along with high-temperature strength and excellent fabricability. This high-performance material 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. RA-33 Wire, in particular, offers unique flexibility for intricate applications requiring corrosion resistance and reliability at elevated temperatures. Below is a detailed overview of its chemical composition, key properties, practical applications, and available product forms.

Chemical Composition

The precisely formulated chemical composition of Alloy 333 (RA-33, UNS N06333) is the foundation of its superior performance in harsh environments. The typical composition (by weight) is as follows:

Nickel (Ni): 45-50% (primary matrix element, providing a stable base for corrosion resistance and high-temperature stability)

Chromium (Cr): 28-32% (a critical component for oxidation resistance, forming a protective oxide layer at elevated temperatures)

Molybdenum (Mo): 15-18% (enhances resistance to pitting, crevice corrosion, and reducing acids, such as hydrochloric acid)

Iron (Fe): ≤ 3.0% (balances the alloy and improves mechanical strength at ambient temperatures)

Tungsten (W): 1.0-2.0% (boosts high-temperature strength and creep resistance)

Carbon (C): ≤ 0.05% (controlled to minimize carbide formation, preserving ductility and corrosion resistance)

Silicon (Si): ≤ 0.5% (aids in deoxidation during manufacturing and enhances oxidation resistance)

Manganese (Mn): ≤ 0.5% (improves fabricability and prevents hot cracking during welding)

Trace elements: Phosphorus (P) ≤ 0.02%, Sulfur (S) ≤ 0.01% (kept low to ensure weldability and grain boundary strength)

This balanced composition synergistically delivers the alloy's signature combination of corrosion resistance, high-temperature strength, and formability, making it ideal for extreme industrial environments.

Key Properties

Alloy 333 (RA-33 Wire, UNS N06333) and its various forms exhibit a robust set of properties that make them indispensable in corrosive and high-temperature applications:

Mechanical Properties (room temperature, annealed condition):

Tensile strength: 750-900 MPa (108,800-130,500 psi)

Yield strength (0.2% offset): 300-400 MPa (43,500-58,000 psi)

Elongation (in 50 mm): 30-40% (excellent ductility, enabling complex forming and welding across all product forms)

Hardness: 180-220 HB (Brinell hardness, indicating good machinability)

High-Temperature Performance:

Thermal stability: Maintains significant strength up to 1000°C (1832°F), with tensile strength remaining above 400 MPa at 800°C (1472°F)

Creep resistance: Exhibits good creep resistance at 700-900°C (1292-1652°F), suitable for long-term service under sustained stress

Oxidation resistance: Resists oxidation in air and combustion gases up to 1100°C (2012°F), forming a dense, self-healing chromium oxide layer

Corrosion Resistance:

Broad-spectrum resistance: Exceptional resistance to both oxidizing acids (e.g., nitric acid) and reducing acids (e.g., hydrochloric, sulfuric acid), outperforming many nickel-based alloys

Pitting and crevice corrosion: Superior resistance to pitting and crevice corrosion in chloride-rich environments, with a Critical Pitting Temperature (CPT) above 40°C (104°F) in 6% FeCl₃ solution

Wet corrosion: Resistant to seawater, brines, and industrial chemicals, including organic acids and alkaline solutions

Stress corrosion cracking (SCC): Highly resistant to SCC in chloride and sulfide environments, even at elevated temperatures

Physical Properties:

Density: 9.2 g/cm³ (0.332 lb/in³)

Thermal conductivity: 11 W/(m·K) at 20°C (68°F), increasing to 18 W/(m·K) at 1000°C (1832°F)

Melting point: 1350-1400°C (2462-2552°F)

Coefficient of thermal expansion: 13.0 μm/(m·K) (20-100°C), rising to 17.0 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 333 (RA-33, UNS N06333) is manufactured in a diverse range of forms to accommodate specialized 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), ideal for machining into valves, pumps, 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 corrosion-resistant gaskets for high-temperature equipment.

Wire: RA-33 Wire (diameters 0.05 mm to 10 mm) offers excellent flexibility for forming thermocouple sheaths, woven mesh screens, and high-temperature springs in corrosive environments.

Rods: Solid cylindrical rods (diameters 3 mm to 50 mm) suitable for structural supports in chemical processing 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 in chemical, petrochemical, and marine applications.

Foil: Ultra-thin sheets (thickness 0.01 mm to 0.1 mm) used in lightweight corrosion barriers and thermal insulation in aerospace and industrial systems.

Plate and Sheet: Flat forms (plate: thickness 5 mm to 100 mm; sheet: 0.3 mm to 5 mm) for fabricating tanks, pressure vessels, and heat exchanger components.

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

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

Applications

The exceptional properties of Alloy 333 (RA-33 Wire, UNS N06333) across its various forms make it a preferred material in industries requiring resistance to extreme corrosion and high temperatures:

Chemical Processing:

Acid production: Tanks and vessels (from plates and sheets) for handling nitric, sulfuric, and hydrochloric acids; tubes for acid transport and heat exchangers.

Pharmaceutical manufacturing: Fittings and valves (machined from bars) for high-purity chemical processing; wire mesh for filtration of corrosive solutions.

Pulp and paper industry: Components exposed to bleaching agents (e.g., chlorine dioxide) and acidic pulping solutions, such as digester liners and agitators.

Petrochemical and Oil & Gas:

Downhole equipment: Tubes and rods for sour gas wells, resisting hydrogen sulfide (H₂S) and chloride corrosion.

Refining: Plates and sheets for catalytic crackers and distillation columns; wire for thermocouple leads in high-temperature, corrosive environments.

Offshore platforms: Pipes for seawater injection systems; bars for fasteners and structural components in marine corrosive environments.

Power Generation:

Waste-to-energy plants: Plates and tubes for boilers and heat exchangers, resisting corrosion from acidic flue gases.

Nuclear power: Components for secondary coolant systems, leveraging resistance to high-temperature water and radiation-induced corrosion.

Biomass power plants: Furnace liners (from plates) and heat exchanger tubes, withstanding corrosive byproducts of biomass combustion.

Specialized Applications by Form:

Wire: Thermocouple sheaths in chemical reactors, woven filters for acid filtration, and high-temperature springs in corrosive machinery.

Tube/Pipe: Process piping in chemical plants, heat exchanger tubes in desalination, and sour gas transport lines.

Plate/Sheet: Tank liners for aggressive chemicals, pressure vessel walls, and heat exchanger panels in power plants.

Bar/Rod: Machined valves, pump shafts, and fasteners for corrosion-prone assemblies in extreme environments.

In summary, Alloy 333 (RA-33 Wire, UNS N06333) — available in forms from Bar and Wire to Plate and Forging Stock — delivers exceptional corrosion resistance across a broad range of environments, high-temperature strength, and versatility. Its diverse product forms enable tailored solutions across chemical processing, petrochemical, and power generation sectors, establishing it as a critical material in extreme 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 2917 gallon liquid totes Special package is available on request.