6. Structural changes after hot forming

The structures resulting from dynamic restoration and continuous or discontinuous dynamic recrystallization processes are generally not stable. During final cooling, or between passes in multi-pass processes, they therefore transform statically, i.e. in the absence of an imposed deformation rate. In fact, it is the characteristics of these static transformations that really determine the structure and properties of hot-formed products.

While there are only two softening mechanisms in the case of annealing carried out on a metal after cold deformation, static restoration and recrystallization, three distinct processes have been identified after high-temperature deformation [25] :

• static restoration ;

• conventional static...