What is the role of annealing?

Annealing is the process of softening steel to relieve internal strain. This makes the steel easier to machine. The metal is heated above the critical temperature and cooled slowly. The most common method is to place the steel in the furnace and heat it thoroughly. Then turn off the furnace, allowing the metal to cool slowly, Another method is to pack the metal in clay , heat it to the critical temperature, remove it from the furnace, and allow it to cool slowly.