The Loss of Tensile Strength of Hard-Drawn Conductors by Annealing in Servicec

Abstract

Although the literature contains many results of tests on the loss of tensile strength of wires held at various temperatures for various time durations, the data are very disperse, and it is difficult to apply them to determine the loss of strength of a particular conductor as a result of long-term annealing in service. This paper examines the effect on the loss of strength of the reduction in cross-sectional area during drawing, the operating temperature, and the time duration of annealing. The effect of the heat capacity of wires and conductors on the loss of strength following a short-circuit or a lightning impulse current is shown. The need for more work to determine the effects of tension and stranding on the loss is stressed.