Conclusions

Surface hardening of alloy steels to depths of around 1 millimeter can be achieved using a nitriding treatment in the ferritic phase. The aim is to achieve high hardness, surface compression and absence of brittleness, in order to increase surface resistance to mechanical and thermal stresses.

Nitrogen transfer in the ferritic solid phase is accompanied in alloy steels by nitride precipitation mechanisms, the nature and morphology of which depend closely on alloy composition and the conditions controlling material transfer.

In recent years, these extremely complex diffusion-precipitation mechanisms in multiphase systems have been rationally analyzed using a global approach: thermodynamic, kinetic and microstructural.

This rational analysis is the result of an ongoing comparison between thermodynamic and kinetic simulation...