Alloy G-3，INCO G-3 Foil，Shim，

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Alloy G-3 (INCO G-3 Wire) - Introduction with Composition, Properties, Applications and Product Forms

Alloy G-3, commercially known as INCO G-3, is a nickel-chromium-molybdenum superalloy engineered for exceptional resistance to both oxidizing and reducing environments, making it highly versatile in diverse corrosive conditions. This high-performance material combines superior corrosion resistance with good mechanical strength and excellent fabricability, and is available in a comprehensive range of forms to meet industrial needs, including Bar (Round bar, Flat bar), Ribbon, Wire, Rods, Tube, Pipe, Foil, Plate, Sheet, Strip, and Forging Stock. INCO G-3 Wire, in particular, offers unique flexibility for intricate applications requiring corrosion resistance in aggressive chemical environments, such as chemical processing and marine 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 G-3 (INCO G-3) is the foundation of its superior performance in both oxidizing and reducing corrosive environments. The typical composition (by weight) is as follows:

Nickel (Ni): 48-54% (primary matrix element, providing a stable base for corrosion resistance and structural integrity)

Chromium (Cr): 21-23% (a critical component for oxidation resistance, forming a protective chromium oxide layer in oxidizing environments)

Molybdenum (Mo): 6-8% (enhances resistance to reducing acids and pitting corrosion in chloride-rich environments)

Iron (Fe): 18-22% (improves fabricability and mechanical stability at ambient and elevated temperatures)

Copper (Cu): 1.5-2.5% (boosts resistance to sulfuric acid and other reducing acids)

Tungsten (W): 1.5-2.5% (aids in reducing pitting and crevice corrosion in aggressive chloride environments)

Manganese (Mn): ≤ 1.0% (assists in deoxidation during manufacturing and improves weldability)

Silicon (Si): ≤ 0.8% (aids in forming a stable oxide layer, enhancing oxidation resistance)

Carbon (C): ≤ 0.03% (controlled to minimize carbide formation, preserving ductility and resistance to intergranular corrosion)

Trace elements: Phosphorus (P) ≤ 0.04%, Sulfur (S) ≤ 0.03% (kept low to ensure weldability and grain boundary strength)

This synergistic composition delivers the alloy's signature versatility, resisting both oxidizing and reducing corrosive environments while maintaining good mechanical properties.

Key Properties

Alloy G-3 (INCO G-3 Wire) and its various forms exhibit a robust set of properties that make them indispensable in diverse corrosive and high-temperature applications:

Mechanical Properties (room temperature, annealed condition):

Tensile strength: 650-790 MPa (94,300-114,600 psi)

Yield strength (0.2% offset): 275-380 MPa (39,900-55,100 psi)

Elongation (in 50 mm): 30-45% (excellent ductility, enabling complex forming and welding across all product forms)

Hardness: 170-210 HB (Brinell hardness, indicating good machinability)

High-Temperature Performance:

Thermal stability: Maintains significant strength up to 800°C (1472°F), with tensile strength remaining above 300 MPa at 650°C (1202°F)

Creep resistance: Exhibits good creep resistance at 500-700°C (932-1292°F), suitable for long-term service under sustained stress in industrial systems

Oxidation resistance: Good resistance to oxidation in air up to 900°C (1652°F), forming a dense, self-healing chromium oxide layer

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

Corrosion Resistance:

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

Chloride resistance: Superior resistance to pitting and crevice corrosion in chloride-rich environments, including seawater and brines, with a high Critical Pitting Temperature (CPT)

Wet corrosion: Resistant to industrial chemicals, alkaline solutions, and organic acids, making it versatile across diverse industries

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

Physical Properties:

Density: 8.1 g/cm³ (0.292 lb/in³)

Thermal conductivity: 13 W/(m·K) at 20°C (68°F), increasing to 22 W/(m·K) at 800°C (1472°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 800°C (1472°F)

Modulus of elasticity: 205 GPa (29,700 ksi) at room temperature, decreasing to 160 GPa (23,200 ksi) at 800°C (1472°F)

Product Forms

Alloy G-3 (INCO G-3) is manufactured in a diverse range of forms to accommodate specialized industrial processes across chemical, marine, and industrial 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 and seals for corrosive equipment.

Wire: INCO G-3 Wire (diameters 0.05 mm to 10 mm) offers excellent flexibility for forming thermocouple sheaths, sensor leads, and woven mesh for filtration in aggressive chemical and marine environments.

Rods: Solid cylindrical rods (diameters 3 mm to 50 mm) suitable for structural supports in chemical reactors, marine systems, and high-temperature processing equipment.

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 seawater, in chemical processing and marine systems.

Foil: Ultra-thin sheets (thickness 0.01 mm to 0.1 mm) used in lightweight corrosion barriers and liners for precision instruments and marine 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 marine structural parts.

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

Forging Stock: Billets and ingots for hot forging into complex shapes such as pump impellers, valve bodies, and marine hardware for aggressive service.

Applications

The exceptional versatility of Alloy G-3 (INCO G-3 Wire) across its various forms makes it a critical material in industries requiring resistance to diverse corrosive environments:

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.

Chemical synthesis: Reactor internals (from forging stock) and heat exchangers (from tube and sheet) for processes involving mixed acid environments.

Marine and Offshore:

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

Offshore 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, resisting chloride-induced pitting.

Petrochemical and Oil & Gas:

Refining: Equipment for handling sour gases and mixed acidic hydrocarbons, including heat exchanger tubes (from tube) and separator vessels (from plate).

Downhole equipment: Components for wells producing acidic hydrocarbons, such as liners (from sheet) and tooling (from bar).

Gas processing: Scrubbers and separators (from plate and sheet) for removing acidic contaminants from natural gas.

Specialized Applications by Form:

Wire: Thermocouple sheaths in mixed acid reactors, sensor leads in marine systems, and woven filters for acid and seawater filtration.

Tube/Pipe: Multi-purpose chemical transport lines, seawater cooling lines, and heat exchanger tubes in diverse industrial systems.

Plate/Sheet: Reactor vessel liners, storage tank walls, and marine structural panels resistant to both acids and saltwater.

Bar/Rod: Machined valves, pump shafts, and fasteners for corrosive environments where exposure to mixed chemicals is common.

In summary, Alloy G-3 (INCO G-3 Wire) — available in forms from Bar and Wire to Plate and Forging Stock — delivers exceptional versatility in resisting both oxidizing and reducing corrosive environments, along with good mechanical strength and formability. Its diverse product forms enable tailored solutions across chemical processing, marine, and petrochemical sectors, establishing it as a critical material in complex corrosive 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 2857 gallon liquid totes Special package is available on request.