Consider the TTT diagram as shown and the cooling curves imposed on the TTT diagram shown in Figure 9. The curve 1 in Figure 9 , where the cooling is very slow is called annealing; annealing, in this case, results in coarse pearlite, as indicated.

Annealing is, in general, an operation that results in softening of the given material; such softening might be a result of annihilation of defects, recrystallisation (if the material is sufficiently cold worked), and growth of grains (and, in general, coarser microstructural features). When annealing process removes the stresses in a cold worked material, such a heat treatment process is known as stress relieving operation.

Normalising is a type of annealing with relatively faster cooling rates; normalising, in steels, as shown, leads to fine pearlite.