The goal of the treatment is to enrich the surface layer of components with nitrogen (nitriding) or nitrogen and carbon (carbonitriding) to achieve a high resistance to wear and a certain resistance to corrosion.
A wear-resistant compound layer consisting of iron nitrides typically forms on the surface. In the diffusion zone beneath this layer, special nitrides that result from the combination of nitrogen with alloying elements serve to increase the hardness and bending strength. The core of the component, which is not enriched with nitrogen, maintains the strength and ductility of the pre-hardened material.
To this end, the material being treated is exposed during nitriding to a nitrogen-emitting or nitrogen- and carbon-emitting atmosphere at temperatures between 500 and 600°C for a defined period of time, which may be up to over 100 hours depending on the nitriding depth. Due to the set concentration gradients between the atmosphere of the furnace and the steel/component, the nitrogen/carbon penetrates into the surface of the component and diffuses into the inside of the workpiece.
Low treatment temperatures prevent structural transformations and therefore delays caused by structural transformations following heat treatment