The manufacturing process of the new copper-aluminum transition clamp requires multi-stage coordinated control to ensure a tight bond between copper and aluminum. Its core lies in eliminating interface defects caused by differences in the chemical properties of the two metals, while simultaneously ensuring mechanical strength and long-term stability. The following analysis examines seven dimensions: material composite, welding process, interface treatment, structural design, quality inspection, environmental control, and process optimization.
The material composite stage is fundamental to ensuring a tight bond. Traditional direct copper-aluminum connections are prone to gaps due to electrochemical corrosion. The new process employs a casting-rolling composite technology, simultaneously casting molten aluminum and copper strips under high temperature and pressure in an oxygen-free environment, allowing them to form a metallurgical bond in a semi-molten state. This process controls the rolling speed and pressure, enabling copper and aluminum atoms to diffuse at the interface, forming a uniform transition layer and avoiding poor bonding caused by insufficient material purity or residual oxide film. Furthermore, after forming, the composite plate undergoes multiple cold rolling and annealing treatments to further eliminate internal stress and improve interface bonding strength.
The choice of welding process directly affects the bonding quality. Friction welding, due to its high energy density and controllability, has become a key technology. During the welding process, the aluminum rod semi-finished product and the copper-aluminum composite plate semi-finished product rotate at high speed and are subjected to pressure. Frictional heat brings the contact surface to a plastic state, and then atomic bonding is achieved under the action of upsetting force. This process effectively avoids voids or cracks caused by the difference in melting points between copper and aluminum during fusion welding. Simultaneously, by controlling the rotation speed and pressure parameters, it ensures a dense metallic bond at the joint surface, eliminating the risk of loosening caused by mechanical interlocking.
Interface treatment is a crucial detail for improving the tightness of the bond. After welding, the joint surface undergoes fine polishing, using multi-stage grinding wheels to gradually refine the surface roughness and eliminate micro-protrusions and depressions. This step not only reduces stress concentration points but also improves conductivity by increasing the actual contact area. Furthermore, surface treatment removes oxide layers or contaminants generated during welding, preventing a decrease in bond strength due to impurities and laying the foundation for corrosion resistance in subsequent use.
The structural design enhances bond stability through geometric optimization. The new copper-aluminum transition clamp adopts an embedded structure, with interlocking textures designed on the contact surface between the copper and aluminum layers. Mechanical interlocking increases resistance to peeling. Meanwhile, an elastic buffer space is reserved at the joint to compensate for the difference in thermal expansion coefficients between copper and aluminum, preventing separation of the joint surface due to temperature changes. This design significantly improves the durability of the transition clip under dynamic loads while ensuring conductivity.
Quality inspection is carried out throughout the entire manufacturing process to ensure reliability. Joint strength testing employs dual verification using tensile and peel tests to ensure that the interface tensile strength meets design requirements. Microstructural analysis uses a metallographic microscope to observe the thickness and uniformity of the transition layer at the joint surface, eliminating defects such as incomplete fusion or brittle phase formation. Non-destructive testing techniques, such as ultrasonic testing, can accurately locate internal microcracks, preventing potential failure risks. These testing methods form a closed-loop control, ensuring that each batch of products meets the standard of tight bonding.
Environmental control is crucial to preventing interface degradation. The manufacturing workshop must maintain constant temperature and humidity conditions to prevent aluminum from absorbing moisture or copper from oxidizing. Local gas protection is used in the welding area to isolate the molten pool from oxygen and nitrogen contamination. Finished products are stored using vacuum packaging or desiccant sealing to prevent electrochemical corrosion caused by a humid environment. Through comprehensive environmental control throughout the process, the bonding life of the transition clip is extended.
Process optimization requires continuous iteration based on experimental feedback. By simulating the bonding performance under different operating conditions, the casting and rolling temperature, friction welding parameters, or interface treatment processes can be adjusted. For example, the coating thickness can be increased for high humidity environments, or the interlocking structure can be optimized for high-frequency vibration scenarios. This application-oriented improvement allows the bonding tightness of the new copper-aluminum transition clamp to continuously approach the theoretical limit, meeting the stringent reliability requirements of fields such as smart grids and rail transportation.
