Annealed Copper Strip for Transformers
2026-06-17
In power transmission and distribution systems, transformers play a crucial role in voltage conversion and power transmission. The performance of the winding materials directly determines the transformer's energy efficiency rating, operational stability, and service life. Haomei Aluminum has been deeply involved in the field of conductive metal materials for many years. Our annealed copper strip for transformers, with its high-purity materials, precision manufacturing processes, and stable performance, has become the preferred substrate for windings in dry-type transformers, oil-immersed transformers, reactors, and instrument transformers.
The annealed copper strip for transformers uses high-purity cathode copper as raw material, with T2 copper (corresponding to national standard C1100 or C11000) as the mainstream material. The copper-silver content is no less than 99.90%, and harmful impurities such as bismuth, antimony, arsenic, and lead are strictly controlled to ensure that the intrinsic conductivity of the material is not compromised. The finished product conductivity can reach over 100% IACS, with some high-precision batches consistently achieving 101% IACS, far exceeding the industry standard. High conductivity translates to lower DC resistance, effectively reducing Joule heat loss in windings under high current conditions and directly improving the overall energy efficiency of the transformer, aligning with the development trend of energy conservation and loss reduction in power grid equipment.
The annealing process is a core step in optimizing the performance of transformer copper strip. Cold-rolled copper strip suffers from severe internal lattice distortion and significant internal stress, resulting in high hardness and poor plasticity, making it prone to cracking and springback during winding. Haomei Aluminum employs a protective atmosphere bright annealing process, completing the recrystallization process in a precisely temperature-controlled furnace to completely eliminate work hardening and residual stress, bringing the copper strip to a fully soft state (O state). The annealed copper strip achieves an elongation of over 30%, with Vickers hardness controlled within the HV60-HV70 range, exhibiting excellent bending and forming performance. It can tightly conform to the curvature of the winding mold, preventing cracks and breaks during winding, and ensuring high coil turn fit, effectively improving winding space utilization.
In terms of dimensional and surface quality control, annealed copper strip for transformers adheres to stringent precision standards. Thickness ranges from 0.1mm to 3.0mm, and width can be customized to customer requirements. Thickness tolerance is controlled at the micron level, and side curvature is no greater than 2mm/m, ensuring smooth material feeding and no deviation during winding. The strip edges undergo precision trimming, eliminating burrs and sharp corners to prevent interlayer discharge and insulation breakdown. The surface is clean, free of oxidation, scratches, and oil spots after brightening, allowing direct compatibility with insulating paper wrapping and impregnation processes without additional surface treatment.
Haomei Aluminum's transformer annealed copper strip advantages lie in its end-to-end quality control. From melting and casting, multi-pass cold rolling to atmosphere-protected annealing and finishing slitting, each process is equipped with online testing equipment to inspect conductivity, mechanical properties, and dimensional accuracy of each roll. Complete material certificates and test reports are included with every shipment. The product is compatible with high-speed continuous production on foil winding machines, and large-roll supply reduces the number of joints and lowers the risk of winding welding defects. We also offer customized solutions based on specific customer operating conditions, such as oxygen-free copper materials and tin-plated anti-oxidation treatments, to meet the manufacturing needs of transformers with different voltage levels and operating environments.
As a core conductive component of power equipment, the quality of annealed copper strip for transformers directly affects the reliability of power grid operation. Haomei Aluminum consistently maintains high industry standards in controlling product quality, continuously optimizing annealing processes and processing precision, and providing stable, efficient, and cost-effective copper strip material solutions for transformer manufacturers worldwide, contributing to the energy efficiency upgrade of power equipment.