Annealing: used for copper, aluminum, brass, and more and uses air-cooling to make them softer. Case hardening: used to harden the outside of the material, usually used for materials that need ductility as well as a durable outer layer. Normalizing: similar to annealing, makes the material software and easier to work with. Hardening: this strengthens and hardens the material by rearranging defects in the microstructure with heat. Tempering: primarily for iron-based alloys that can be brittle, tempering lowers this and maintains hardness.