Popular Science of Contact Welding and its Application in Silver Brazed Electrical Contacts

Contact welding is a welding process that joins materials by applying pressure and utilizing the resistance heat generated by an electric current; it is a type of pressure welding. Resistance welding does not require filler metal. Contact welding is clearly defined as an important branch of pressure welding, achieving material joining through the combined action of mechanical pressure and resistance heat. This process encompasses various techniques, such as resistance welding (mainly including spot welding, seam welding, projection welding, and butt welding), and friction welding, and can be adapted to the welding requirements of Silver Brazed Electrical Contacts.

The welding process relies on two key elements:

1. Pressure Application: External mechanical force brings the workpieces into close contact.

2. Resistance Heating: The instantaneous high heat is generated due to the resistance effect when current passes through the contact surface.

This combined thermo-pressure action brings the metal to a molten or plastic state, achieving metallurgical bonding and providing the technological foundation for stable welding of Welded Electrical Contact Parts.

Spot welding involves pressing the workpieces between two cylindrical electrodes, heating them with electricity to melt the workpieces at the contact point, forming a weld nugget, then disconnecting the power and allowing solidification under pressure to form a dense weld spot. Spot welding is suitable for welding thin plates (lap joints) less than 4 mm thick and reinforcing bars, and is widely used in the production of automobiles, aircraft, electronics, instruments, and everyday consumer goods. It can be used for basic welding of Brazed Silver Contact Assemblies.

Seam welding is similar to spot welding, except that rotating disc electrodes are used instead of cylindrical electrodes. The overlapping workpieces are pressurized and energized between the discs and fed in as the discs rotate, forming a continuous weld seam. Seam welding is suitable for welding lap joints of thin plates less than 3 mm thick, and is mainly used in the production of sealed containers and pipes. It can be used with Copper Silver Welded Contacts to achieve sealing welding.

The main methods of resistance welding also include projection welding and butt welding. Depending on the welding process, butt welding can be divided into resistance butt welding and flash butt welding. Both methods are suitable for the welding requirements of Custom Electrical Contact Components. The resistance butt welding process involves first applying upsetting pressure (10–15 MPa) to ensure tight contact between the workpieces. Electricity is then applied to heat the workpieces to a plastic state. Next, upsetting pressure (30–50 MPa) is applied while the power is simultaneously cut off, causing plastic deformation at the contact point under pressure, thus welding the parts together. Resistance butt welding is simple to operate and produces a smooth joint. However, it requires high precision in the machining and cleaning of the workpiece end faces. Otherwise, uneven heating of the contact surface can occur, leading to defects such as oxide inclusions and incomplete penetration, affecting weld quality. Therefore, it is generally only used for welding workpieces with a diameter less than 20 mm, simple cross-sections, and low stress, including small silver-brazed electrical contacts.

The flash butt welding process involves first applying electricity, then bringing the two workpieces into slight contact. Due to the uneven surfaces of the workpieces, the current density at the contact point is very high, causing the metal to rapidly melt, vaporize, and explode, producing sparks and creating a flash phenomenon. Continuing to move the workpieces creates new contact points, and the flash phenomenon continues. Once both workpiece ends are completely melted, pressure is rapidly applied, then the power is cut off, and pressure is applied again to weld the workpieces together. Flash butt welding produces high-quality joints and requires less pre-welding surface cleaning. It is often used for welding critical workpieces subjected to high stress. It can weld not only the same metal but also dissimilar metals such as aluminum-steel and aluminum-copper, and can weld various specifications of AgCu Contact Assemblies for Switchgear.

In the 1950s, high-frequency welding technology began to develop and be applied to welded pipe production. Its basic categories include high-frequency contact welding and high-frequency induction welding. Contact welding involves a pair of copper electrodes contacting the two sides of the steel pipe being welded. It offers good induced current penetration, high welding efficiency, and low power consumption, making it widely used in high-speed, low-precision pipe production and thick-walled stainless steel welded pipe production. However, its current stability is affected by the workpiece surface quality, and the electrodes wear out relatively quickly. Using Silver Tipped Electrical Contacts can effectively improve welding stability.

Besides contact welding methods that primarily use resistance heat, friction welding, ultrasonic welding, diffusion welding, and explosive welding also fall under the category of pressure welding, where connections are achieved by applying pressure. All of these can be used in conjunction with Brazed Electrical Contacts to broaden application scenarios.

Based on the core advantages and application requirements of contact welding, our Silver Brazed Electrical Contacts are perfectly compatible with various contact welding processes, especially suitable for high-frequency contact welding and resistance brazing.

Electrical Contact Assemblies uses a high-purity silver alloy as the base material, with added copper, nickel, and other elements to optimize the formula. It possesses excellent electrical conductivity, thermal conductivity, and mechanical strength. The joint tensile strength can reach 150-220MPa, with extremely low contact resistance, effectively reducing energy loss. It also exhibits strong corrosion resistance, adapting to harsh environments such as humidity and salt spray. Simultaneously, it precisely matches the hot-press composite process of contact welding, resulting in a small heat-affected zone and high welding stability. It is widely used in power electronics, automotive electronics, circuit breakers, and other equipment requiring high-reliability connections.

We can customize Silver Brazed Electrical Contacts parameters according to your specific welding needs and workpiece specifications. The quality has undergone rigorous testing to ensure welding results and product durability throughout the entire process. Feel free to contact us at any time for product details, customized solutions, and to discuss placing an order.