Journal of Materials Science, Vol.34, No.17, 4239-4244, 1999
Characterization of fire-refined copper recycled from scrap
Certain properties of fire-refined copper recycled from scrap have been characterized. A method is presented to calculate the half-softening temperature and the annealing temperature that allows 30% elongation to failure, hereinafter referred to as epsilon(30%) temperature, on the basis of hardness measurements. The relation between ultimate strain and ultimate elongation has been studied and is described by a mathematicale xpression that seems to be independent of copper composition and annealing temperature. The microstructure of annealed samples reveals that recrystallization begins at half-softening temperature, and is ending at epsilon(30%) temperature, although grain growth is not observed. An optimal range of oxygen content has been found that gives the minimum epsilon(30%) temperature for each studied composition, and a mathematical expression with which to calculate those minimum temperatures is developed. The influence of cold-working degree on epsilon(30%) temperature is also described; these temperatures reach a constant minimum value for each composition at high deformation degrees of cold-working.