Nitrogen Solid Solution Diffusion
Nitrogen substitutional diffusion is the thermally activated exchange of nitrogen atoms between different crystal cells in the metal lattice. This affects aging and tempering kinetics.
Physicochemical Mechanism of Action
Nitrogen solid-solution diffusion describes the process by which nitrogen atoms in the metal lattice move from one crystal cell to another. This exchange is activated by thermal energy and influences the diffusion rate.
Metallurgical Relevance & Risks in Welding
This diffusion can promote the aging of steel by transporting nitrogen into the surface of the material. This can lead to a coarser grain structure and reduce the toughness of the steel. Furthermore, it affects tempering kinetics, which can impair the mechanical properties of the weld.
Workshop Practice & Action Guidelines
To minimize nitrogen solid-solution diffusion, it is important to ensure careful control of welding parameters such as temperature and time. For high-quality steel grades, use a low hot gas flow and a short post-weld heat treatment. For critical applications, the use of shielding gases like argon may also be recommended.