Influence of Copper Quality and Annealing Process on Softness of Enamelled Wires

Copper material quality and the annealing process are critical factors influencing the softness of enamelled wires. To enhance the softness and meet high-performance application requirements, the effects of these factors were investigated by analyzing the metallographic structure, elongation, and springback angle of wires prepared from different copper materials under various processes. The results indicated that lower impurity content, grain refinement, and a uniform microstructure in the copper material effectively increased the elongation and reduced the springback angle of the wires. When the first annealing temperature/the second annealing temperature was 550 °C/540 °C and the annealing line speed was 70 m·min⁻¹, the elongation and springback angle of the enameled wire were the best, which were 44.1% and 32.0°, respectively.