What Does Heat Treatment Mean?
Heat treatment is a process that is used to alter the physical properties of a material in a beneficial way. During a heat treatment process, a material is typically heated to a target temperature at which its physical properties change. It is then cooled at a controlled rate.
Corrosionpedia Explains Heat Treatment
Heat treatment is used for several reasons:
- To anneal or normalize a metal. If a metal has been hardened due to work or heat, then annealing or normalizing may be employed to bring it back to a softer, more ductile state. During the annealing process, the metal is heated above its recrystallization temperature and then cooled very slowly in a furnace or by some other heating method. Normalizing is the same as annealing, except that the metal is air cooled rather than furnace cooled. The metal being heat-treated must be considered heat treatable for any effect to occur.
- To harden a material. For this process, a material is heated above a certain temperature. The material is then rapidly quenched by a media such as water or oil. This rapid quenching will create a harder, stronger material when performed on a hardenable material.
Applications for heat treatment are abundant. Gears and shafts are frequently hardened through heat treatment to resist wear and indentation. Metals that require ductility and toughness, such as structural steels, may need to be annealed or normalized if they are subjected to cold working.