Normalize

Create a more uniform grain structure
Normalizing is similar to conventional annealing, except that when the heating cycle is complete, the furnace is opened and the parts are allowed to cool in still air. This causes a more rapid cooling of the parts, leaving them still with a more uniform grain structure but one that is generally harder and stronger than with annealing. Normalizing is very common for pressure vessel plate grades like A516, where the uniform structure and higher mechanical properties are desirable. This process is also applied to certain lower carbon alloy grades that would be too soft to machine if annealed.