Optimization of gaseous nitriding of steels by multi-physics modelling

Abstract

Gaseous nitriding is controlled by temperature, time and surface nitrogen potential. Tuning these parameters lead to the expected mechanical properties (hardness, residual stresses) and durability of treated mechanical parts. In this paper, a methodology is proposed to optimize nitriding parameters by using a multi-physics modelling of the nitriding treatment (microstructure, diffusion/precipitation mechanisms, hardness and residual stress generation). This model is particularly suited to the diffusion layer and does not apply to the compound layer. The scope concerns low-alloyed carbon steels and gaseous nitriding. The role of carbon is established and taken into account in the proposed methodology.