Which processing step involves heating copper and then cooling it to increase ductility?

• A. Quenching
• B. Annealing
• C. Hardening
• D. Tempering

Answer: (B)

Annealing is the heat-treatment step that increases ductility in copper. By heating copper to a high temperature, the crystal structure can rearrange and dislocations can move and annihilate, a process called recrystallization. Slow cooling then allows new, strain-free grains to form, producing a softer, more ductile metal that’s easier to form in subsequent work. Quick cooling or quenching would trap stresses and usually harden the metal rather than make it more ductile, while hardening or tempering concepts are aimed at increasing hardness or reducing brittleness after hardening, typically in steels rather than in copper.