Annealing, in metallurgy and materials science, is a heat treatment wherein a material is altered, causing changes in its properties such as strength and hardness.

It is a process that produces conditions by heating to above the recrystallization temperature, maintaining a suitable temperature, and then cooling.

Annealing is used to induce ductility, soften material, relieve internal stresses, refine the structure by making it homogeneous, and improve cold working properties.

There are 3 stages which in full annealing which are stated as follows:

Recovery Phase-

Here crystal defects are removed by softening the metal and make the grain strain free, as well as all the internal stresses are eliminated.

Recrystallization Phase -

Here annealing is done up to recrystallization phase so that further grain growth should be stopped to maintain strength of metal. Plus the newly form grains starts nucleating and grow to replace the grains formed by internal stresses.

Grain Growth Phase -

After recrystallization stage the grain continues to grow, and the grain boundary will migrate and large grains will be formed by same energy as that of smaller one.

The steel formed is reached to austenitic crystal structure or austenite-cementite structure depends on steel used for annealing.

The steel is furnace cooled for longer time and the taken