Alloy 405,Monel 405 Sheet,UNS N04405

Alloy 405,Monel 405 Wire,UNS N04405

Introduction to Alloy 405 (Monel 405 Wire, UNS N04405)

Alloy 405, commercially known as Monel 405 and classified under UNS N04405, is a low-carbon nickel-copper superalloy derived from the classic Monel 400 (UNS N04400) — engineered to retain exceptional corrosion resistance while addressing a key limitation of its predecessor: weldability. By reducing carbon content to ≤0.05 wt%, Monel 405 minimizes carbide precipitation at grain boundaries during welding and high-temperature service, eliminating the risk of intergranular corrosion (IGC) that can compromise welded joints in harsh environments. This alloy operates reliably from cryogenic conditions (-253°C/-423°F) up to 480°C/900°F, leveraging a solid-solution strengthened austenitic microstructure to deliver consistent ductility, toughness, and resistance to seawater, brines, organic acids, and reducing chemicals. Monel 405 wire, a specialized form of this alloy, is widely used in welding-intensive applications across marine engineering, chemical processing, and oil & gas industries—excelling in components like welded wire mesh, valve stems, and downhole sensor cables that require both corrosion resilience and robust welded connections.

1. Chemical Composition (Typical, wt%)

The chemical composition of UNS N04405 adheres to strict industry standards including ASTM B865 (for nickel-copper alloy wire), ASTM B164 (for nickel-copper alloy sheet/plate), and ASME SB865, with the low-carbon design being its defining feature. The typical composition is as follows:

Element

Content Range (wt%)

Function

Nickel (Ni)

63.0 - 67.0

Serves as the primary matrix element, stabilizing the austenitic structure; enhances resistance to reducing environments (e.g., H₂S, sulfuric acid) and maintains ductility at cryogenic temperatures.

Copper (Cu)

28.0 - 34.0

A core alloying element that boosts corrosion resistance in seawater, brines, and organic acids (e.g., acetic acid); improves workability during wire drawing and welding.

Carbon (C)

≤ 0.05

The defining low-carbon feature—minimized to prevent chromium or nickel carbide precipitation at grain boundaries, eliminating intergranular corrosion (IGC) in welded joints or high-temperature service.

Iron (Fe)

≤ 2.5

Improves hot workability (critical for wire rod production) and controls alloy cost; limited to avoid compromising corrosion resistance in marine or chemical environments.

Manganese (Mn)

≤ 1.5

Aids in deoxidation during melting and improves cold workability for fine wire drawing; controlled to avoid brittleness at low temperatures.

Silicon (Si)

≤ 0.5

Reduces oxide formation during hot processing and improves molten alloy fluidity for casting; limited to avoid excessive inclusions that degrade fatigue life.

Sulfur (S)

≤ 0.010

Strictly limited to prevent hot cracking during wire drawing and welding; reduces the risk of pitting corrosion in sulfur-rich environments (e.g., sour gas wells).

Phosphorus (P)

≤ 0.015

Controlled to avoid grain boundary embrittlement, especially in welded components exposed to cyclic loading or cryogenic temperatures.

Cobalt (Co)

≤ 1.0

Trace element that slightly enhances high-temperature strength without interfering with corrosion resistance; limited to avoid increasing alloy cost.

2. Physical Properties

Monel 405 wire exhibits stable physical properties across its operating temperature range, with performance driven by solid-solution strengthening (no age hardening required—simplifying manufacturing). Key properties (measured at room temperature unless specified otherwise) are:

Property

Value

Test Condition

Density

8.80 g/cm³

Room temperature (25°C)

Melting Point Range

1300 - 1350°C

-

Thermal Expansion Coefficient

13.3 × 10⁻⁶/°C

20 - 100°C; 16.0 × 10⁻⁶/°C (20 - 400°C)

Thermal Conductivity

22.7 W/(m·K)

100°C; 29.1 W/(m·K) (400°C)

Electrical Resistivity

0.54 × 10⁻⁶ Ω·m

Room temperature (25°C); 0.62 × 10⁻⁶ Ω·m (400°C)

Modulus of Elasticity

180 GPa

Room temperature (tensile); 155 GPa (400°C)

Poisson’s Ratio

0.32

Room temperature

Curie Temperature

≈ -196°C

Below this temperature, weakly ferromagnetic (irrelevant for most application temperatures).

Tensile Strength

≥ 650 MPa

Room temperature; ≥ 400 MPa (400°C)

Yield Strength (0.2% Offset)

≥ 275 MPa

Room temperature; ≥ 200 MPa (400°C)

Elongation

≥ 40%

Room temperature; ≥ 45% (-196°C, liquid nitrogen)

Hardness (Annealed)

≤ 180 HB

Room temperature

Impact Toughness (Charpy V-Notch)

≥ 120 J

Room temperature; ≥ 80 J (-196°C)

Corrosion Resistance

Passes 2000-hour salt spray test (ASTM B117); No intergranular corrosion (ASTM A262 Practice E)

5% NaCl solution, 35°C (salt spray); Boiling nitric acid (晶间腐蚀测试)

3. Production Process of Monel 405 Wire

The manufacturing of Monel 405 wire focuses on strict carbon control (≤0.05 wt%) and optimized processing to preserve its corrosion resistance and weldability. Unlike precipitation-hardened alloys, no age hardening is required—simplifying the workflow. Key steps include:

3.1 Raw Material Melting & Casting (Low-Carbon Focus)

Melting: High-purity raw materials (nickel, copper, iron, etc.) are melted via vacuum induction melting (VIM) followed by argon oxygen decarburization (AOD). This dual process ensures precise carbon control (≤0.05 wt%), eliminates gaseous impurities (O₂ < 20 ppm, N₂ < 30 ppm), and ensures uniform distribution of nickel and copper—critical for consistent corrosion performance.

Casting: Molten alloy is cast into ingots (500 - 2500 kg) or blooms, which undergo homogenization annealing at 1050 - 1100°C for 8 - 10 hours. This step eliminates chemical segregation (especially of copper and nickel) and dissolves any residual microcarbides, preparing the material for hot working while preserving the low-carbon microstructure.

3.2 Hot Working & Wire Rod Production

Hot Rolling: Ingots/blooms are hot-rolled at 950 - 1050°C into wire rods (diameter: 8 - 20 mm). Hot rolling is performed at a controlled temperature range to avoid grain coarsening; rods are air-cooled to room temperature at a rate of 50 - 80°C/hour to maintain the austenitic phase and prevent unintended carbide formation.

Descaling: Hot-rolled rods undergo shot blasting (to remove loose oxide scale) followed by acid pickling (nitric-hydrofluoric acid solution) to eliminate residual nickel-copper oxide layers. This step prevents surface defects during cold drawing and ensures clean surfaces for welding (critical for avoiding weld contamination).

3.3 Cold Drawing (Wire Formation)

Multi-Pass Cold Drawing: Wire rods are cold-drawn through diamond dies in 6 - 10 passes to achieve the desired diameter (typically 0.1 mm - 10 mm). Each pass reduces diameter by 12 - 20%, with intermediate annealing (950 - 1000°C for 30 - 45 minutes, water-quenched) between passes. This annealing step relieves work hardening, restores ductility, and ensures no carbide precipitation (thanks to low carbon content)—critical for maintaining weldability.

Dimensional Control: Tension, die alignment, and drawing speed are precisely regulated to maintain tight diameter tolerance (±0.015 mm for precision wire) and roundness (≤0.008 mm). For welding applications (e.g., wire mesh, filler wire), laser diameter monitoring ensures consistency—uneven wire diameter can cause weld bead defects.

3.4 Final Heat Treatment (Weldability & Stability)

Monel 405 wire undergoes stress-relief annealing to optimize its performance, especially for welded applications:

Stress Relief: Heating the wire to 850 - 900°C for 1 - 2 hours, followed by air cooling. This step reduces residual stresses from cold drawing, stabilizes the austenitic microstructure, and confirms no carbide formation—ensuring the wire maintains corrosion resistance and weldability even after welding.

Weld Pre-Conditioning (Optional): For wire used as welding filler or in welded assemblies, an additional low-temperature anneal (600 - 650°C for 1 hour) is performed. This step further refines the microstructure, ensuring the heat-affected zone (HAZ) during welding does not form carbides.

3.5 Surface Finishing & Quality Inspection

Surface Treatment:

Pickling: Post-annealing pickling in nitric acid to remove oxide scales and enhance the natural nickel-copper corrosion-resistant film—critical for marine or chemical environments.

Passivation: Optional chromate treatment to further strengthen the surface film, ideal for applications exposed to chloride ions (e.g., seawater welding).

Polishing: For high-precision welding or food-grade applications, the wire is polished to a smooth surface finish (Ra ≤ 0.2 μm) to avoid weld contamination and ensure hygiene compliance.

Quality Control:

Chemical Analysis: Optical emission spectroscopy (OES) to verify carbon content (≤0.05 wt%) and nickel-copper ratio—critical for corrosion resistance and weldability.

Mechanical Testing: Tensile testing (strength/elongation), hardness testing (HB), and bend testing (to confirm ductility for welding).

Corrosion Testing: Salt spray testing (ASTM B117), intergranular corrosion testing (ASTM A262 Practice E), and weld corrosion testing (ASTM G36)—to validate no IGC in welded joints.

Non-Destructive Testing: Eddy current testing (for surface defects like cracks) and ultrasonic testing (for internal flaws)—essential for welding filler wire, where defects can propagate into welds.

Weldability Validation: Trial TIG/MIG welds using the wire, followed by metallographic analysis of the HAZ to confirm no carbide precipitation.

4. Product Applications

Monel 405 wire’s unique combination of low-carbon-driven weldability, exceptional corrosion resistance, and ductility makes it indispensable in welding-intensive, corrosive environments:

4.1 Marine Engineering (Welding-Centric Applications)

Subsea Welded Assemblies: Wire (0.5 - 2.0 mm) for manufacturing welded wire mesh screens, subsea pipeline connectors, and ROV (Remote Operated Vehicle) welded components—resists seawater corrosion and ensures welded joints do not suffer from IGC.

Naval Vessels: Wire for welded hull fasteners, heat exchanger tubes, and propeller shaft welded sleeves—outperforms carbon steel in saltwater, with welded joints maintaining corrosion resistance.

Coastal Infrastructure: Wire for welded reinforcement in seawater intake structures and port equipment—welded connections resist tidal corrosion and salt spray.

4.2 Chemical & Petrochemical Industry

Welded Process Equipment: Wire for welded wire mesh filters, valve stems in welded valves, and sensor cables in welded reactors—resists organic acids (e.g., acetic acid) and reducing chemicals, with welded joints remaining corrosion-free.

Pharmaceutical & Food Processing: Wire for welded sanitary equipment (e.g., mixer blades, filter screens)—low carbon content avoids contamination, and welded joints comply with FDA standards (21 CFR Part 177) for food/drug contact.

4.3 Oil & Gas Industry

Downhole Welded Tools: Wire for welded downhole sensor cables, valve actuators, and wellhead welded components—resists sour gas (H₂S) and brine corrosion, with welded joints surviving high pressure (up to 15,000 psi) and moderate temperatures (up to 400°C).

Offshore Platforms: Wire for welded structural supports, pipeline repair sleeves, and firewater system welded components—welded joints maintain integrity in marine atmospheric corrosion.

4.4 Aerospace & Cryogenic Applications

Cryogenic Welded Systems: Wire for welded liquid oxygen (LOX) or liquid hydrogen (LH₂) tank components—maintains ductility at -196°C to -253°C and welds do not suffer from IGC or brittle fracture.

Aerospace Welded Fasteners: Wire for small-diameter welded fasteners in aircraft fuel systems—resists jet fuel corrosion and ensures welded joints are leak-free.

4.5 Industrial Welding & Fabrication

Welding Filler Wire: Monel 405 wire (1.0 - 4.0 mm) is used as filler wire for welding Monel 400/405 components—matches the base metal’s corrosion resistance and ensures no IGC in the HAZ.

Welded Electrical Components: Wire for welded electrical connectors in corrosive environments (e.g., chemical plant control systems)—maintains conductivity and resists chemical-induced corrosion.

Conclusion

Alloy 405 (Monel 405 Wire, UNS N04405) is a specialized low-carbon nickel-copper superalloy wire, distinguished by its ability to combine Monel’s legendary corrosion resistance with enhanced weldability—eliminating intergranular corrosion in welded joints. Its low-carbon design, solid-solution strengthening, and consistent performance across cryogenic to moderate high temperatures make it a critical material for welding-intensive applications in marine, chemical, and oil & gas industries. Whether used as welded wire mesh, filler wire, or downhole sensor cables, Monel 405 wire delivers reliable corrosion resistance and robust welded connections. For custom requirements—such as ultra-precision welding wire (down to 0.05 mm diameter), food-grade surface finishes, or large-diameter wire (up to 12 mm) for structural welding—manufacturers offer tailored solutions to meet the most demanding welded corrosion challenges.

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 678 gallon liquid totes Special package is available on request.