The goal of this thesis was to develop a model for structural surface modifications in metal cutting. Cutting tests on steel AISI 4140 (42CrMo4) showed that dynamic recrystallization (DRX) formed nano-crystalline surface layers. The kinetics of DRX were analytically modeled by the thermodynamic Helmholtz potential, considering the internal energy as well as the production and flow of entropy. Finally, DRX was predicted in finite element simulations and process signature components were compiled.