Anneal is a process used to heat and cool metal in order to make it more durable and resistant to damage. It involves heating the metal to a certain temperature and then cooling it slowly, allowing the metal to become more malleable and less brittle. The related terms TEMPER, HARDEN, STIFFEN, and STRENGTHEN all refer to different stages of the annealing process. Tempering is the process of heating the metal to a specific temperature and then cooling it quickly, which makes the metal harder and more resistant to damage. Hardening is the process of heating the metal to a higher temperature and then cooling it quickly, which makes the metal even harder and more resistant to damage. Stiffening is the process of heating the metal to a higher temperature and then cooling it slowly, which makes the metal more rigid and less prone to bending or breaking. Strengthening is the process of heating the metal to a higher temperature and then cooling it slowly, which makes the metal stronger and more resistant to damage.