Alloy 401，Monel 401 ，

British Specs:，American Specs:，German Specs:

Alloy 401 and Monel 401 Foil, Shim - Introduction with Composition, Properties, Applications and Product Forms

Alloy 401, commercially known as Monel 401, is a nickel-copper alloy recognized for its excellent corrosion resistance in various environments, good mechanical strength, and superior formability. This versatile material is available in a wide range of forms to cater to diverse industrial requirements, including Bar (Round bar, Flat bar), Ribbon, Wire, Rods, Tube, Pipe, Foil, Plate, Sheet, Strip, and Forging Stock. Among these, Monel 401 Foil and Shim are highly valued for their thin gauges and precision, making them ideal for specialized applications requiring tight tolerances and corrosion resistance. Below is a detailed overview of its chemical composition, key properties, practical applications, and available product forms.

Chemical Composition

The well-balanced chemical composition of Alloy 401 (Monel 401) is crucial to its exceptional performance. The typical composition (by weight) is as follows:

Nickel (Ni): 54-58% (serves as the primary matrix element, providing excellent corrosion resistance and structural stability)

Copper (Cu): 40-44% (enhances machinability and contributes to corrosion resistance in both oxidizing and reducing environments)

Iron (Fe): ≤ 1.0% (improves mechanical strength and resistance to pitting in certain corrosive media)

Manganese (Mn): ≤ 0.5% (aids in deoxidation during manufacturing and enhances fabricability)

Carbon (C): ≤ 0.15% (controlled to prevent carbide formation that could reduce ductility)

Silicon (Si): ≤ 0.5% (assists in the formation of a protective oxide layer, enhancing oxidation resistance)

Trace elements: Sulfur (S) ≤ 0.01% (kept at low levels to ensure good ductility and weldability)

This composition synergistically delivers the alloy's characteristic combination of corrosion resistance, mechanical properties, and formability, making it suitable for a wide range of industrial applications.

Key Properties

Alloy 401 and its various forms, including Monel 401 Foil and Shim, exhibit a set of impressive properties that make them highly desirable in corrosive and precision-oriented environments:

Mechanical Properties (room temperature, annealed condition):

Tensile strength: 500-600 MPa (72,500-87,000 psi)

Yield strength (0.2% offset): 200-250 MPa (29,000-36,300 psi)

Elongation (in 50 mm): 35-45% (excellent ductility, allowing for easy forming, bending, and fabrication of thin products like foil and shim)

Hardness: 130-170 HB (Brinell hardness, indicating good machinability)

Corrosion Resistance:

General corrosion resistance: Excellent resistance to seawater, brines, and various industrial chemicals, including sulfuric acid (dilute), hydrochloric acid (dilute), and alkaline solutions

Pitting and crevice corrosion: Good resistance to pitting and crevice corrosion in chloride-containing environments, making it suitable for marine and coastal applications

Oxidation resistance: Maintains resistance to oxidation in air up to 400°C (752°F), with gradual reduction in performance at higher temperatures

Galvanic corrosion: Resistant to galvanic corrosion when in contact with other metals, reducing the risk of degradation in multi-material assemblies

Physical Properties:

Density: 8.8 g/cm³ (0.318 lb/in³)

Thermal conductivity: 23 W/(m·K) at 20°C (68°F)

Melting point: 1300-1350°C (2372-2462°F)

Coefficient of thermal expansion: 14.0 μm/(m·K) (20-100°C)

Modulus of elasticity: 180 GPa (26,100 ksi) at room temperature

Product Forms

Alloy 401 (Monel 401) is manufactured in a diverse range of forms to accommodate various 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 valves, pumps, and marine hardware.

Ribbon: Thin, flat strips (thickness 0.1 mm to 2 mm, width 5 mm to 100 mm) used in electrical components and corrosion-resistant gaskets.

Wire: Monel 401 Wire (diameters 0.05 mm to 10 mm) offers excellent flexibility for forming springs, screens, and electrical contacts in corrosive environments.

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

Tube and Pipe: Seamless and welded options (outer diameter 6 mm to 200 mm, wall thickness 0.5 mm to 20 mm) for fluid transport in chemical processing and marine applications.

Foil: Ultra-thin sheets (thickness 0.005 mm to 0.1 mm) with precise thickness control, used in lightweight corrosion barriers, electrical insulation, and gasketing. Monel 401 Foil is particularly valued for its uniformity and ability to conform to complex surfaces.

Shim: Thin, flat pieces (thickness 0.01 mm to 1 mm, various sizes) designed for precise spacing, alignment, and leveling in machinery and equipment. Monel 401 Shim provides corrosion resistance and dimensional stability in 

critical assemblies.

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 marine structural parts.

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

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

Applications

The exceptional properties of Alloy 401 (Monel 401) across its various forms make it a preferred material in industries requiring corrosion resistance and reliable performance in harsh environments:

Marine and Offshore:

Shipbuilding: Sheets and plates for hull components, propeller shafts, and seawater intake systems; bars for fasteners and fittings. Monel 401 Foil is used for corrosion-resistant wrapping and gasketing in marine joints.

Offshore platforms: Tubes and pipes for seawater processing; wire for rigging and screens; plates for storage tanks. Shim made from Monel 401 ensures precise alignment of critical offshore machinery.

Desalination plants: Tubes for heat exchangers; sheets for pressure vessels; rods for pump components, resisting saltwater corrosion.

Chemical Processing:

Acid production: Tanks and vessels (from plates and sheets) for storing and processing sulfuric and hydrochloric acids; tubes for chemical transport. Monel 401 Foil is used as a protective lining in small-scale acid containers.

Pharmaceutical manufacturing: Fittings and valves (machined from bars) for handling high-purity chemicals; wire mesh for filtration. Shim ensures precise alignment in pharmaceutical processing equipment.

Pulp and paper industry: Components exposed to bleaching agents and corrosive pulping solutions, such as pumps and agitators.

Industrial and Electrical:

Valves and pumps: Cast or machined parts from bar and forging stock, offering corrosion resistance in aggressive fluids.

Electrical components: Wire for connectors and contacts in marine or chemical environments; ribbon for heating elements in corrosive atmospheres. Foil is used for electrical insulation in corrosive environments.

Springs and fasteners: Wire formed into springs for marine equipment; bolts and nuts from bar stock for corrosion-prone assemblies. Shim is used to adjust spring tension and fastener alignment.

Specialized Applications by Form:

Foil: Lightweight corrosion barriers in aerospace components, electrical insulation in chemical plants, and gaskets for precision instruments.

Shim: Precise spacing in engine assemblies, alignment of machine tools, and leveling of heavy equipment in corrosive environments.

Wire: Woven screens for seawater filtration, springs in chemical pumps, and electrical leads in corrosive environments.

Tube/Pipe: Process piping in chemical plants, heat exchanger tubes in desalination, and seawater cooling lines.

In summary, Alloy 401 (Monel 401) — available in forms from Bar and Wire to Foil, Shim, and Forging Stock — delivers exceptional corrosion resistance, good mechanical strength, and versatility. Its diverse product forms, including the precision-oriented Foil and Shim, enable tailored solutions across marine, chemical processing, and industrial sectors, establishing it as a critical material in corrosion-prone 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 2924 gallon liquid totes Special package is available on request.