What is typically required to obtain soft or annealed copper wire from hard drawn wire?

To obtain soft or annealed copper wire from hard drawn wire, heating is the essential process involved. Heat treatment, specifically annealing, involves raising the temperature of the hard drawn wire to a specific level, which allows the internal structure of the metal to reorganize. This helps to relieve stresses that have accumulated during the drawing process and reduces dislocations in the crystal structure of the copper, resulting in a softer and more ductile material.

During the annealing process, the wire is heated and then cooled slowly, which enables the atoms in the copper to move more freely and align in a way that reduces hardness and increases malleability. This transformation makes the wire easier to work with for applications requiring flexibility and ease of manipulation.

Although other processes like mechanical stress relief or chemical treatments can affect material properties, they do not serve the purpose of transforming hard drawn wire to annealed wire in the same effective manner as heating does. Therefore, heating is the correct requirement for achieving the desired characteristic of soft copper wire.