Manganese copper strip is a bimetallic composite material formed by electron beam welding of manganese copper and copper. It has unique resistance stability and excellent conductivity. It is the core material for manufacturing manganese copper shunts of magnetic latching relays. As one of the key components of the magnetic latching relay of the electric meter, the manganese copper shunt is directly related to the accuracy of electric energy measurement and the stable operation of the system.
Overview of manganese copper strip
1. Definition
Manganese copper strip is a new functional composite material, which is mainly composed of the resistance precision alloy manganese copper (MnCu) and highly conductive copper (T2 or T3) through an electron beam welding process. This structure combines the precise resistance characteristics of manganese copper and the excellent conductivity of copper. It is widely used in scenarios that require precise current detection and resistance value control, especially for the manufacture of Manganin Shunt for Electricity Meters of electric meter magnetic latching relays.
2. Material composition
Manganese copper layer (MnCu): mainly provides stable and low-temperature drift resistance characteristics;
Copper layer (T2/T3): provides good conductivity and structural support.
Table: Comparison of technical parameters of typical Customizable Copper Manganin Shunt Resistor alloy strips
| Performance indicators | 6J13 manganese copper | 9 F1 manganese copper | 2 BMn3-127 | Application focus |
| Resistivity (μΩ·m) | 0.44-0.47 | 0.40-0.48 | 0.40-0.48 | Ultra-high precision measurement |
| Resistance temperature coefficient | (×10⁻⁶/℃) Within ±5 | Within ±20 | Within ±40 | Stable in a wide temperature range |
| Thermoelectric potential to copper | (μV/℃) ≤0.5 | ≤2 | ≤2 | Low thermal noise circuit |
| Tensile strength (MPa) | ≥440 | ≥390 | ≥440 | Structural strength requirements |
| Operating temperature range (℃) | -60~+150 | 0~80 | 0~70 | Extreme environment applications |
The physical properties of the Manganin Copper Shunt strip are very special: the density is about 8.4g/cm³, which is between copper (8.9) and nickel (8.9); the melting point is about 980℃, the thermal expansion coefficient is low, and it shows stable dimensional characteristics when the temperature changes8. These characteristics make it an ideal choice for precision resistor components. In terms of electrical performance, the typical resistivity of manganese copper is 0.40-0.48μΩ·m, which is higher than pure copper but extremely stable; its core advantage lies in its extremely low-temperature coefficient of resistance (high-quality grades can reach within ±5×10⁻⁶/℃), which ensures that the resistance value changes very little under different ambient temperatures9. In addition, the thermoelectric potential of manganese copper to copper is very low (≤2μV/℃), which avoids temperature measurement errors, which is crucial for precision current detection.
Electron beam welding composite process
1. Process principle
Electron beam welding is a high-energy beam welding process that achieves efficient instantaneous fusion by impacting the material surface with a focused high-speed electron beam under vacuum conditions. Copper Manganin Shunt strip uses this technology to linearly compound manganese copper strip and copper strip to make them one.
2. Process advantages
High bonding strength: no interlayer, no delamination, strong interface bonding;
Small thermal impact: stable material structure and controlled thermal deformation;
High dimensional accuracy: suitable for high-precision stamping parts;
Environmentally friendly and pollution-free: clean process, no added flux, and soldering flux.
Table: Comparison of key parameters of electron beam welding of manganese copper shunt
| Process parameters | Preheating stage | Primary welding | Insulation stage | Secondary welding | Heat treatment |
| Voltage (kV) | 110-150 | 110-150 | 110-150 | 110-150 | 110-150 |
| Focusing current (mA) | 20-25 | 20-25 | 20-25 | 20-25 | 35-45 |
| Electron beam current (mA) | 3-5 | 3-5 | 3-5 | 3-5 | 3-5 |
| Welding speed (mm/s) | 10-15 | 15-20 | 5-10 | 15-20 | 15-20 |
Technical parameters and international standards
1. Technical parameter example (MnCu + T2 composite tape)
| Item | Typical value or range |
| Total thickness | 0.2mm\~0.6mm |
| Composite method | Single-sided/double-sided manganese copper composite |
| Interlayer thickness ratio | Manganese copper: copper = 1:1\~1:4 |
| Width tolerance | ±0.05mm |
| Tensile strength (after composite) | ≥300 MPa (depending on the copper substrate) |
| Bending radius | ≤2 times the thickness of the plate, no cracks |
| Surface roughness | ≤Ra 0.8μm |
| Resistance value deviation | Within ±1% (depending on the shunt design) |
2. Corresponding international brands (with manganese copper as the core)
| Country/Region | Material Brand | Standard |
| China GB | 6J13, 0Cr20Mn80 | GB/T 5233 |
| USA ASTM | Manganin | ASTM B386, B267 |
| German DIN | CuMn12Ni | DIN 43760 |
| Japanese JIS | C7200 | JIS H3100 |
Physical and electrical property
1. Physical properties (manganese copper layer)
Density: about 8.4 g/cm³;
Linear expansion coefficient: 17×10⁻⁶/°C;
Thermal conductivity: about 25 W/m·K;
Good ductility: suitable for precision stamping and multiple bending;
Good welding and formability.
2. Electrical performance
Resistivity: 0.43\~0.47 μΩ·m (25℃);
Temperature coefficient of resistance (TCR): ±(10\~30)×10⁻⁶/K;
Resistance value stability: The resistance value deviation is less than ±1% after long-term use;
Long electrical life: Especially suitable for long-term stable operation in the meter environment.
Processing methods and surface treatment
1. Stamping
Manganese Copper Shunts are suitable for high-precision automatic stamping dies. The manufacturing process needs to control the following key points:
Dimensional accuracy control: The tolerance is controlled within ±0.02mm;
Crack-free forming: Ensure the stability of the interface between manganese copper and copper;
Stamping die life: Use hard steel dies with regular maintenance;
Precision positioning punching: Ensure the electrical matching and installation accuracy of manganese copper shunts.
2. Surface treatment method
Surface treatment of Magnetic Shunt Customized is crucial to improving its electrical reliability and corrosion resistance. Common treatment methods are as follows:
| Treatment method | Functional description |
| Degreasing + passivation | Remove oil and oxide film to improve subsequent weldability or coating adhesion |
| Electroplating nickel (Ni) | Improve corrosion resistance and electrical contact performance |
| Local electroplating tin (Sn) | Improve welding performance and adapt to SMT or welding assembly requirements |
| Laser coding | Realize batch traceability and product sequence management |
| Mirror polishing | Improve the conductivity of the contact area and reduce contact resistance |
Table: Common defects and solutions for manganese copper shunt stamping parts
| Defect type | Cause | Impact on performance | Corrective measures |
| Excessive burrs | Improper mold clearance or wear | Increased contact resistance, measurement error | Optimize clearance and regularly repair molds |
| Dimensional tolerance | Uncompensated material rebound | Difficult assembly, poor contact | Adjust the bending angle and add shaping stations |
| Surface scratches | Contamination of mold or feeding system | Corrosion resistance decreases | Clean mold and use protective film |
| Resistance fluctuation | Uneven stress in the material | Reduced measurement accuracy | Add low-temperature annealing process |
The heat treatment process is crucial to the performance stability of manganese copper terminals. The stamped terminals need to be annealed at low temperatures (250-300℃ for 1-2 hours) to eliminate processing stress and avoid resistance value drift in subsequent use. For military or metrology-grade shunts with high precision requirements, a deformation heat treatment process can be used: annealing at 400-450℃ after cold deformation, so that the tensile strength is maintained above 450MPa, while the resistance temperature coefficient is further reduced by 79. The heat treatment process needs to be carried out in an inert gas or vacuum environment to prevent oxidation of the Manganese Copper Stamping surface.
Application field analysis
1. Manganese copper shunt terminal of electric meter magnetic latching relay
Stamping parts made of Manganese Copper Stamping strips are mainly used for:
Magnetic latching relay manganese copper terminal: As part of the relay current channel, it has a stable resistance value characteristic;
Manganese copper shunt structure: Accurately shunt current and control opening and closing conditions;
Current sampling connector: Cooperate with the main control chip to collect electric energy metering information.
2. Key role in electric energy metering system
Current measurement benchmark: Resistance value stability directly determines the accuracy of electric meter data;
Strong temperature stability: Adapt to the long-term outdoor operation requirements of electric meters in different regions;
Strong corrosion and oxidation resistance: Extend the overall service life of the relay;
Suitable for a variety of installation structures: Can be adapted to welding or plug-in assembly after surface treatment.
Table: Key performance indicators of manganese copper shunts for smart meters
| Performance parameters | Civilian requirements | Industrial requirements | Metering requirements | Test method |
| Basic error | ±0.5% | ±0.2% | ±0.1% | Standard current source comparison |
| Temperature coefficient | ±50ppm/℃ | ±20ppm/℃ | ±5ppm/℃ | Temperature chamber step test |
| Long-term stability | 0.1%/year | 0.05%/year | 0.02%/year | 85℃/1000h aging |
| Overload capacity | 20In/1s | 50In/1s | 100In/0.1s | Pulse current test |
| Insulation resistance | ≥100MΩ | ≥500MΩ | ≥1000MΩ |
3. New energy and smart terminal equipment
With the development of the Internet of Things, smart grids, and new energy power systems, Electric Current Measure Manganin Shunts are also used in:
Distributed energy storage cabinet sampling module
New energy vehicle battery BMS management module
Intelligent sampling control unit for industrial power supply
Key points of quality control
1. Material testing
Composition testing (XRF/ICP) controls the purity of manganese copper and copper materials;
Layer thickness testing (ultrasound/slice microscopy) ensures a uniform composite ratio.
2. Processing quality control
Stamping part size and hole position detection: use 2.5D imaging equipment and caliper comparison;
Surface treatment uniformity detection: thickness, electroplating adhesion, foreign matter removal;
Accurate resistance value measurement: use a high-precision four-wire measurement method to control deviation ≤±1%.
As a composite functional alloy copper material, the Manganese Copper Shunts strip is the key raw material for manufacturing Manganin Copper Shunts of electric meter magnetic latching relays. It uses electron beam welding technology to achieve an efficient combination of manganese copper and copper and meets the stringent requirements of high-strength stamping and long-term operation of electric meters while ensuring accurate resistance and excellent conductivity. With the rapid development of smart grids and green energy technology, manganese copper shunts will play an increasingly core role in the field of electrical measurement and control.
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