nitrocarburized

Nitrocarburizing is a thermochemical surface hardening process used to improve the wear resistance, fatigue strength, and corrosion resistance of steel components. It involves diffusing both nitrogen and carbon into the surface layer of the metal at elevated temperatures, typically between 500 and 600 degrees Celsius. The process is carried out in a controlled atmosphere, often generated by gas mixtures containing ammonia and carbon-containing compounds like hydrocarbons.

The nitrocarburizing process creates a compound layer on the surface of the steel, which is rich in nitrides and carbides. Beneath this compound layer, a diffusion zone is formed where nitrogen and carbon atoms have penetrated into the steel's microstructure, forming a hardened layer. The depth of this diffusion zone and the characteristics of the compound layer can be controlled by adjusting the process parameters such as temperature, time, and the composition of the treatment atmosphere.

Compared to other surface hardening methods like carburizing or nitriding, nitrocarburizing generally offers a more uniform case depth, particularly on complex geometries. It also typically results in less distortion of the component. The resulting surface is often a pale grey or black color, depending on the specific process variant and post-treatment. Nitrocarburized parts are widely used in applications such as automotive components (e.g., crankshafts, camshafts), gears, tooling, and firearms where enhanced surface properties are critical for performance and longevity.