Development of Overhead Insulated Drawn Copper Wire with Improved Stress Corrosion Cracking durability

Abstract

In this paper, we investigated alloying, crystal grain growing, annealing of copper wire to improve the SCC (Stress-Corrosion-Cracking) durability. Each treatment is effective, in particular, alloying with Ag and annealing are most effective. Varying the concentration of silver and the condition of annealing, the sample alloyed with 0.15Ag wt% and annealed under 260°C is most effective. In accelerated test, it was found that the SCC durability of this sample is improved to be 4 times larger than that of conventional copper wire. We also study the mechanism with which the SCC durability is improved. As the result, we revealed that Ag-dense layers exist. It seemed that this Ag-dense layers block the growth of oxide film and the spreading of pitting corrosion, as the result, SCC durability is improved.
Above mentioned, increase in peel strength, weakening of residual distortion stress by annealing, and preventing corrosion and pitting corrosion to spread by Ag-dense layers seemed increase the SCC durability of copper wire with combined effect.