Sequence and Characteristics of structural changes of forging Parts (Part I)

Sequence and Characteristics of structural changes of forging Parts (Part I)
In the process of forging parts gradually forming, its softening process is the main role of dynamic recovery, its structure will also have a certain change. In what order and in what way do the forging pieces change, and what are the characteristics that emerge as a result? The forged parts will have subsequent reaming requirements, and what are the methods in this respect?

In the initial stage of forging deformation, a high density of dislocations will be formed. These dislocations may be evenly distributed or become the subgrain boundaries of the brittle substructure. It can also be observed in cold deformation. When the softening process is not obvious, this stage of thermal deformation can be named hot work hardening stage.

Then, in the second stage of the structural change of forged parts, polygonal subgrain boundaries are formed due to the enhancement of the softening process, and there is a relatively high free dislocation density in the subgrain boundary region. During the deformation process, the polygon substructure gradually replaces the hot working structure. And the multilateral substructure itself changes, resulting in nearly equiaxed subgrains.