Heat Treating: Normalizing
Normalizing is a heat treating process used to austentize a material by heating to approximately 55 °C above the temperature at which ferrite is completely transformed to austenite. *View diagram* The metal is then cooled at room temperature improving its microstructure. The cooling process distinguishes normalizing from annealing as the normalizing process involves air cooling allowing it to cool a bit more quickly than the annealing process. This process can improve machinability and is often used to prepare a metal for hardening. Normalizing is commonly used as a post-treatment to forging, machining, or casting, and a pre-treatment to quenching and tempering.
Photo credit: Christophe Dang Ngoc Chan- CC BY-SA 3.0