What best describes annealing in metals?

• A. Heating and slow cooling to remove stresses, soften the metal and increase ductility; usually reduces hardness.
• B. Rapid cooling to harden the surface.
• C. Heating only enough to melt the surface.
• D. Cooling in air to harden

Answer: (A)

Annealing is a heat-treatment where metal is heated to a suitable temperature, held momentarily, and then cooled slowly. This slow cooling gives the grains time to reorganize through recrystallization, relieving internal stresses and creating a softer, more uniform, and ductile structure. As a result, the material becomes easier to form, machine, or shape, and its hardness typically decreases.

This differs from rapid cooling, which aims to harden the material (quenching), and from processes that heat only the surface or are meant to harden rather than soften.