Metal welding is a key process for connecting different metal materials using heat or pressure. It is widely used in industries such as electronics and power, new energy, automobiles, and photovoltaics. The stability, conductivity, and service life of welded components depends largely on the type of welding substrate, the choice of welding process, the adaptation of solder, and the surface treatment after welding.
Common welding substrates and welding characteristics
1. Welding of copper terminals and copper terminals: Copper has excellent electrical conductivity and thermal conductivity and is a common material for power connectors. It has good welding performance and is highly adaptable to most welding processes, especially suitable for high-temperature metal soldering and resistance brazing.
2. Welding of brass terminals and brass terminals: Brass has high strength and good corrosion resistance and is suitable for the manufacture of structural parts and connectors, but its conductivity is slightly worse than that of copper. Zinc evaporation is easy to occur during welding, so it is necessary to select an appropriate welding temperature and welding method, which is generally more suitable for resistance brazing and high-frequency brazing.
3. Welding of copper terminals and brass terminals: When welding dissimilar metals, problems such as inconsistent thermal expansion and electrochemical corrosion are prone to occur. Therefore, appropriate solder and temperature control strategies must be used. Metal laser welding or resistance brazing is usually recommended.
Comparison of welding process types
| Welding process | Description of characteristics | Applicable materials | Advantages | Disadvantages | Typical applications |
| Metal high-temperature soldering | Connection is achieved by melting tin-based solder at high temperature, generally manual or semi-automatic operation | Copper/brass | Simple process, low cost, suitable for small batches | Inconsistent solder joint size, medium strength | Small power connectors, sample proofing |
| Metal resistance brazing | Melt solder or workpiece with the help of resistance heat formed by current passing through the contact surface | Copper/brass/copper and brass | High-temperature control accuracy, suitable for batch automation | Large equipment investment, high requirements for welding surface cleanliness | Relay exposed terminals, busbar connectors |
| Metal high-frequency brazing | Local heating using high-frequency induction current | Brass/copper/dissimilar metals | Fast heating, small heat-affected zone, fine solder joints | High requirements for workpiece shape | High-frequency induction coil, power plug assembly |
| Metal laser welding | Use a high-energy laser beam to partially melt metal to form a connection | Copper/brass/dissimilar metals | No contact, small deformation, high efficiency | High positioning accuracy requirements, expensive equipment | High-end busbar, film capacitor output end |
Welding assembly process quality control
Material pretreatment
All copper, brass, and other substrate surfaces must be degreased and deoxidized to ensure surface cleanliness to improve welding strength and conductivity;
01
Welding temperature control
According to the type of solder and the thermal conductivity of the substrate, set the optimal temperature zone to prevent overheating deformation or cold welding;
02
Pressure and clamping control
Especially in resistance brazing and laser welding, the pressure must be strictly controlled to ensure complete fusion of the welding area;
03
Workpiece positioning accuracy
For laser welding and high-frequency brazing, the workpiece needs to be clamped with high precision to ensure the consistency of the weld;
04
Online inspection and random inspection
Quality judgment is carried out through image recognition, X-ray inspection, conduction test, etc.
05
Surface treatment after welding
After the welding assembly is completed, surface treatment needs to be carried out according to the product use environment to enhance its anti-oxidation, conductivity, and aesthetic performance.
| Surface treatment process | Applicable materials | Function | Features |
| Tin plating | Copper/brass | Improve weldability and oxidation resistance | Commonly used for tin soldering parts, low-cost |
| Nickel plating | Copper/brass | Anti-corrosion, improve surface hardness | Good wear resistance, suitable for high-current components |
| Silver plating | Copper/brass | Improve conductivity and contact performance | High cost, used for high-performance products |
| Spraying protective paint | All materials | Insulation, dustproof, and life extension | Moderate cost, suitable for industrial products |
Typical application areas of welding components
1. Exposed terminals of power magnetic latching relays: require stable conductivity and high mechanical strength, recommend copper terminal and copper terminal welding, and use resistance brazing or laser welding.
2. Busbar connection of new energy vehicle film capacitors: require high voltage and high temperature resistance, suitable for copper terminal and brass terminal welding, recommend high-frequency brazing or laser welding.
3. Contact caps for new energy vehicles and photovoltaic fuses: high strength and corrosion resistance are required, and metal resistance brazing or laser welding is recommended.
In actual production, the selection of welding technology needs to comprehensively consider the type of metal substrate, usage scenario, current density requirements, batch size, and cost control. The welding process of copper terminals and copper terminals is stable and has strong adaptability; the welding of brass terminals and brass terminals needs to pay attention to the evaporation control of zinc; the welding of copper terminals and brass terminals needs to use high-precision welding methods to avoid dissimilar metal reactions. Compared with traditional welding methods, metal resistance brazing, metal high-frequency brazing, and metal laser welding are more suitable for the processing of large-scale, high-precision products, especially in the wide application of new energy vehicles and photovoltaic industries, providing technical guarantees for the quality and consistency of welding components.
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