Identifying the influence of technological factors on the structure and properties of contact wire from secondary copper

Abstract

This paper reports the analysis of studies on the use of secondary copper for the production of articles based on it, namely the contact wire for electric transport. The effect of the drawing step on the macro- and microstructure and physical and mechanical properties of the copper wire was studied. The optimal draw pitch for continuous copper casting is 8.2 mm. At a temperature of the melt (casting) of 1200 °C and a draw step of 8.2 mm, the average crystallization rate is ~300 °C/s. This provides sufficient time for crystallization, and with such parameters, the heat transfer from the metal receiver does not have a noticeable effect on the structure. At the same time, it was established that Mg is a modifier for liquid Cu while all other elements do not have such an effect and form solid solutions with copper. It is shown that the increase in the concentration of silver from 0.082 at% to 0.092 at% led to an increase in specific electrical resistance by 0.582 %. As for other elements, namely, iron, the change in its amount from 0.002 at% to 0.005 at% increased the specific resistance of copper by 1.733 %. The change in nickel concentration from 0.024 at% to 0.036 at% and tin from 0.0010 at% to 0.0035 at% led to its growth by 2.927 % and 1.269 %, respectively