The nuclei may form by subgrain growth and/or grain boundary migration. As a result of polygonization, it might be possible to produce a subgrain capable of growing out into surrounding polygonized matrix.

If grain has 6 boundaries, y will be planar and structure metastable. However, if total number of boundaries around grain is less than 6, each boundary must be concave inwards.

Recrystallization temperature is temperature at which a particular metal with a particular amount of cold deformation will completely recrystallized in a finite period of time, usually 1 hr.

During recovery, some of stored internal strain energy is relieved by virtue of dislocation motion, as a result of enhanced atomic diffusion at elevated temperature.

As deformation before annealing is reduced to smaller and smaller values, rate of nucleation falls much faster than rate of growth. As a consequence, ratio N to G decreases in magnitude with decreasing strain and is effectively zero at several percent elongation.

In an isormal anneal, rate at which a recovery process occurs always decreases with time; that is, it starts rapidly and proceeds at a slower and slower rate as driving force for reaction is expended.

Cold working increases strength, hardness, and electrical resistance, and it decreases ductility. In recovery stage of annealing, physical and mechanical properties that suffered changes as a result of cold working tend to recover ir original values.

Tighter binding of atoms on concave side of boundary should make rate at which atoms jump across boundary from convex to concave crystal greater than that in opposite direction. The greater curvature of boundary, n greater should be this effect, and faster movement of crystal boundary.

Modern recrystallization ory indicates that activation energy generally does not remain a constant throughout recrystallization process. In most cases, activation energy changes continuously during recrystallization as driving force for recrystallization, stored energy of cold work, is depleted.

Isormal annealing consists of four steps. The first step is heating steel components similar as in case of full annealing. The second step is slightly fast cooling from usual austenitizing temperature to a constant temperature just below A1. The third step is to hold at this reduced temperature for sufficient soaking period for completion of transformation and final step involves cooling steel component to room temperature in air.