How does the new copper-aluminum transition clamp effectively prevent contact degradation caused by thermal expansion and contraction?
Publish Time: 2026-01-05
In high-voltage power systems, connecting copper and aluminum conductors has long been a technical challenge. Copper and aluminum not only have different electrical conductivities, but their coefficients of thermal expansion also differ significantly. When current flows, the joint heats up due to resistance; after power is cut off or the load is reduced, it gradually cools down. This repeated thermal cycle causes the two metals to expand and contract at different rates. Over time, the originally tight contact surface may develop tiny gaps, loosen, or even oxidize, resulting in "contact degradation." This process not only increases resistance and causes localized overheating, but can also evolve into arcing, ablation, or even circuit breaker failures. The new copper-aluminum transition clamp addresses this core problem by systematically innovating materials, structure, and processes, fundamentally improving the thermal stability and long-term reliability of the connection.The key lies in eliminating interface voids and achieving a metallurgically dense bond. Traditional mechanical crimping or simple socketing methods often fail to completely eliminate the microscopic air layer between the copper and aluminum contact surfaces. Once heated, these gaps become stress concentration points, accelerating material creep and interface separation. The new copper-aluminum transition clamp features a V-shaped groove precisely machined into the inner wall of the copper sleeve, combined with high-pressure die casting and aluminum welding processes. This allows molten aluminum to fully fill the groove under high pressure and form a strong bond with the copper substrate. This structure not only significantly increases the actual contact area but also creates a composite interface of "mechanical interlocking + metallurgical diffusion" after cooling. Even with slight dimensional changes caused by temperature variations, the geometric constraints of the V-shaped groove effectively resist the displacement tendency of the aluminum material, preventing interface separation.Simultaneously, the densification treatment of the material itself provides a solid foundation for resistance to thermal fatigue. The transition clamp body is made of T2 high-purity copper rod, formed through cold extrusion and forging processes. This process not only improves the grain density of the copper material but also optimizes its internal microstructure, enabling it to maintain high strength and creep resistance even at high temperatures. The dense copper substrate is less prone to plastic deformation during thermal cycling, thus providing a stable "skeleton" for the entire connection structure and preventing the aluminum end from loosening due to softening and collapse of the copper end.Furthermore, the integrated molding process eliminates the weak points of traditional multi-part assembly. Older transition terminals were often assembled from copper lugs, aluminum sleeves, and fastening bolts, with multiple potential points of loosening between components. The new copper-aluminum transition clamp, through one-time molding or welding, fuses the copper and aluminum parts into a single unit, eliminating additional connectors and the accumulation of assembly tolerances. This "monolithic" design greatly reduces discontinuities in the thermal stress transmission path, allowing the entire joint to deform collaboratively like a single material during temperature changes, significantly reducing the risk of internal stress concentration and fatigue cracking.More importantly, the dense, gapless interface itself inhibits electrochemical corrosion. Copper and aluminum are prone to forming a galvanic cell effect in humid environments, accelerating the oxidation and corrosion of aluminum. The corrosion products (such as aluminum oxide) are high-resistance insulators, further deteriorating contact performance. The new copper-aluminum transition clamp physically blocks corrosion pathways by completely filling the interface and isolating it from air and moisture intrusion, ensuring the connection area remains clean and electrically conductive during long-term operation.In summary, the new copper-aluminum transition clamp effectively prevents contact degradation caused by thermal expansion and contraction not through a single technological breakthrough, but through multiple safeguards including V-groove mechanical anchoring, high-pressure welding for dense bonding, a high-strength, dense copper substrate, and an integrated structural design. This creates a stable connection system even under multi-field coupling of heat, electricity, and force. It allows copper and aluminum, two seemingly disparate metals, to truly coexist harmoniously and reliably under the test of high-voltage current—this is not only a technological advancement but also a silent safeguard for the safety baseline of power systems.
