Simulace procesů nitridace a karbonitridace
In the past there have been many attempts to predict nitriding and nitrocarburizing results. Most of the existing scientific work has been focusing on applying thermodynamics on pure iron and binary or ternary alloys with nitride-forming elements and/or carbon.
While in pure iron, solubility for nitrogen and interfaces to Fe4N and Fe2-3N nitrides can be derived from the iron-nitrogen phase diagram and likewise the solubilities for nitrogen and carbon and the resulting interfaces to Fe3C cementite and
Fe2-3NC carbonitrides can be derived from the iron-nitrogen-carbon phase diagram, the presence of nitride and carbide forming elements in real steels has a tremendous influence on the growth kinetics of the diffusion layer as well as of the compound layer. In addition, when treating steel parts, the pre-nitriding condition of the material has to be taken into account.
This paper will present a new approach were thermodynamic and kinetic effects are calculated based on material composition and pre-nitrided condition. The model is able to simulate up to three-stage recipes with varying temperature and nitriding as well as carburizing potentials, also taking nucleation time into account. The simulation result is giving compound layer thickness, precipitation layer and total diffusion depth and calculates surface hardness, core hardness and effective case depth (core + 50 HV).