MONEL Alloy 401 ,UNS N04401; Monel Nickel-Copper Alloy，1

### **Product Introduction: MONEL® Alloy 401 (UNS N04401)** **MONEL® Alloy 401** is a specialized nickel-copper alloy engineered primarily for its specific electrical properties, including a controlled, nearly constant electrical resistivity over a wide temperature range and a very low thermoelectric force against copper. While it shares its base nickel-copper system with the more common MONEL 400, Alloy 401 is a distinct composition optimized for electrical and electronic applications, particularly where stable resistance and low thermal EMF are critical. It is characterized by excellent ductility, good corrosion resistance, and the ability to be easily joined, making it a preferred material for precision electrical components. --- ### **International Standards & Material Equivalents** MONEL Alloy 401 is defined by its UNS number and is covered under several material standards. | Standard Type | Standard Number | Designation / Title | | :--- | :--- | :--- | | **UNS (USA)** | **N04401** | **MONEL Alloy 401** | | **ASTM (USA)** | B163 | Specification for Seamless Condenser and Heat-Exchanger Tubes (Can include N04401) | | **ASTM (USA)** | F96 | Specification for Electronic Grade Alloys (Covers wire for electronic applications) | | **DIN (Germany)** | 17751 | NiCu30Mn | | **Werkstoff Nr.** | **2.4370** | 2.4370 | > **Note:** The primary identifier is **UNS N04401**. Its specifications are often found in standards for electronic-grade materials and specific forms like wire and strip. --- ### **Chemical Composition** The composition is balanced to achieve its unique electrical characteristics, with a higher manganese content compared to other nickel-copper alloys. | Element | Content (%) | | :--- | :--- | | **Nickel (Ni)** | 40.0 - 45.0 | | **Copper (Cu)** | Balance | | **Manganese (Mn)** | 0.75 - 1.5 | | **Iron (Fe)** | 1.0 max. | | **Carbon (C)** | 0.15 max. | | **Silicon (Si)** | 0.25 max. | | **Sulfur (S)** | 0.015 max. | --- ### **Physical Properties** The physical properties of MONEL 401 are dominated by its electrical characteristics, which are its key selling point. | Property | Value | | :--- | :--- | | **Density** | 8.91 g/cm³ (0.322 lb/in³) | | **Melting Point** | ~1490 °C (~2710 °F) | | **Thermal Conductivity** | 24.9 W/m·K (at 20°C) | | **Electrical Resistivity** | **0.49 μΩ·m** (at 20°C) - *Remains remarkably constant with temperature change* | | **Mean Coefficient of Thermal Expansion** | 14.2 μm/m·°C (20-300°C) | | **Modulus of Elasticity** | 158 GPa (23 x 10⁶ psi) | | **Curie Temperature** | -10 °C to +10 °C (Essentially non-magnetic at room temperature) | --- ### **Mechanical Properties (Typical for Annealed Condition)** Supplied in a soft, annealed condition, it offers high ductility for forming and winding. | Property | Value (Annealed) | | :--- | :--- | | **Tensile Strength** | 380 - 480 MPa (55 - 70 ksi) | | **Yield Strength (0.2% Offset)** | 125 - 250 MPa (18 - 36 ksi) | | **Elongation** | 35% - 45% | | **Hardness (Rockwell B)** | 50 - 70 HRB | --- ### **Key Characteristics & Advantages** 1. **Controlled and Constant Electrical Resistivity:** Its most critical feature. The resistivity changes very little with temperature fluctuations, making it ideal for precision resistors. 2. **Very Low Thermoelectric EMF vs. Copper:** This property is crucial for applications where the alloy is connected to copper, as it minimizes parasitic voltages caused by temperature differences at junctions. 3. **Excellent Ductility and Formability:** Can be easily drawn into fine wire, stamped, and formed into complex shapes. 4. **Good Corrosion Resistance:** Inherits good general corrosion resistance from the nickel-copper system, suitable for many atmospheric and mild chemical environments. 5. **Good Weldability and Solderability:** Can be readily joined using common techniques without significant degradation of its properties. --- ### **Product Applications** MONEL Alloy 401 is almost exclusively used in electrical and electronic applications that leverage its unique properties. * **Precision Resistors:** * Wire-wound resistors for electrical instruments. * Precision potentiometers and rheostats. * **Electrical and Electronic Components:** * Lead wires for transistors and other semiconductors. * Spring contacts, connectors, and conductive springs. * Base and lead material for crystal diodes. * **Thermocouple and Instrumentation Wires:** * Used in compensation cables and extension wires where its low EMF against copper is critical. * Internal wiring for electrical instruments and meters. --- ### **Comparison with Other MONEL Alloys** * **vs. MONEL Alloy 400 (UNS N04400):** While both are Ni-Cu alloys, their purposes differ significantly. MONEL 400 is a general-purpose corrosion-resistant alloy with higher strength. **MONEL 401 is a specialist electrical alloy** with a tailored composition for stable resistivity and low thermal EMF. * **vs. MONEL Alloy R-405 (UNS N04405):** Alloy R-405 is a free-machining version of Alloy 400, not designed for electrical properties. ### **Summary** **MONEL Alloy 401 (UNS N04401)** is a highly specialized, nickel-copper alloy formulated not for extreme corrosion resistance or strength, but for its **exceptional and stable electrical properties**. Its nearly constant electrical resistivity over a temperature range and its minimal thermoelectric effect when paired with copper make it an indispensable material in the world of precision electronics, resistors, and sensitive instrumentation. It is the material of choice when electrical performance, not just mechanical or chemical resistance, is the primary design criterion.

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 3292 gallon liquid totes Special package is available on request.