Rheology and metal forming of fire-refined copper

Fire-refined (FR) copper has a high content of impurities, particularly oxygen, whose interdendritic segregation in the as-cast material causes a pronounced decrease in its ductility. Because of this, it has to be melted and deoxidized before it can be subjected to plastic deformation, thereby making the entire process much more expensive. The present study investigates the use of hot-rolling of as-cast material as an alternative method of providing sufficient ductility to permit subsequent cold deformation without the need for remelting for deoxidation. It is concluded that the required ductility can be obtained through hot-rolling at temperatures between 800 and 900 °C, with reduction of around 30%, and low strain rate conditions. This treatment brought about dynamic recrystallization and dispersion of Cu2O particles in the matrix, resulting at room temperature, elongation at rupture values of 50%, twice the value of 25% obtained from as-cast material.