Carbonitriding

Carbonitriding can be defined as a modified variant of carburizing. Carbon and nitrogen are simultaneously diffused into the surface layer of the component. Carried out by adding ammonia gas to the carburizing atmosphere, this process leverages the hardenability enhancing effect of nitrogen to achieve results at lower temperatures and shorter processing times compared to standard carburizing.

Carbonitriding is typically performed under a controlled atmosphere within a temperature range of 820–900°C. During the process, nitrogen is co diffused into the steel surface alongside carbon at a concentration of approximately 0.2–0.4%. Following the diffusion stage, the components are usually oil quenched to achieve full hardness.

The resulting hardened case depth depends on processing temperature and duration, as well as the steel's hardenability, cooling conditions, and part geometry.