The influence of grain orientation on the stored energy during cold rolling of steels - Experimental evidence and finite element simulation

In order to understand the role of the stored energy within individual grai ns of a deformed polycrystal during the nucleation step of recrystallizatio n, a finite element code has been used to characterise in some details the deformed state of an aggregate of grains after rolling. This code takes exp licitly into account the crystallographic nature of the material, and inclu des a physically-based hardening law of individual slip systems, enabling u s to calculate an average dislocation density within each grain after each deformation step. The presented simulations of large plane strain deformati on have been performed on an aggregate of 343 cubic grains, asociated with 343 initially randomly distributed orientations. It is thus possible to fol low during deformation the global texture and deformation evolutions and al so to get more local information within deformed grains, such as reorientat ions, average intra and intercrystalline misorientations and dislocation de nsities. It is thus found that the predicted texture evolution is in good a greement with the experimental one measured after various rolling strains; also, at the end of the simulated rolling process, the so-called gamma orie ntations are predicted to be the hardest, i.e. associated with maximum disl ocation density. This result is finally discussed, together with preliminar y calculations of intragranular misorientations in the context of nucleatio n.