Nitriding and nitrocarburizing process

Nitriding is a thermochemical treatment in which nitrogen diffuses into the surface of steel to increase hardness, wear resistance and fatigue strength.

Nitrocarburizing is a related process that introduces both nitrogen and carbon into the surface by adding propane or methane.

The Nitrding treatment depth is time- and temperature-dependent, and the process is carried out under a controlled atmosphere. Specific nitriding steels allow the formation of hard nitrides (ε, γ’).

The nitriding process typically produces a two-layer structure: a compound layer and a diffusion layer, whose formation depends on the nitriding potential.

Nitrocarburizing reduces cycle time and allows greater control of layer composition.
Temperature for nitriding processes generally ranges from 490 °C to 560 °C, depending on material and desired layer characteristics.

Temperature profile for nitriding process

Nitriding requires stable thermal conditions and precise atmosphere regulation to achieve the desired microstructure.

Atmospheres used:

Ammonia (NH₃)
Cracked ammonia
Nitrogen with propane or methane addition
Hydrogen probe or NH3 infrared analyzer for precise control of nitriding potential

Through accurate regulation of gas composition, the process can promote either the compound layer or the diffusion layer, or a tailored combination.

Technical principles of nitriding

Nitriding and nitrocarburizing are used to significantly improve the surface properties of steels while minimizing distortion thanks to low treatment temperatures.

Increased surface hardness
Higher wear resistance
Reduced friction with a controlled compound layer
Improved load-bearing capacity (with optimized diffusion depth)
Adjustable layer depth depending on application
Excellent heat resistance

These treatments enhance lifespan and performance, especially for components under heavy contact loads.

Codere expertise in nitriding and nitrocarburizing

Codere provides advanced controlled-atmosphere furnaces designed specifically for nitriding and nitrocarburizing, ensuring precision, repeatability and compliance with demanding industrial standards.

Codere’s nitriding systems allow perfect reproducibility of diffusion layers and compound layers according to customer requirements.

CRG6Ni furnace with a hydrogen measurement probe or an infrared analyzer for ammonia
Accurate control of Kn, Kc and Ko nitriding parameters
Stable gas distribution and temperature uniformity
Optional cooling system to accelerate cycle time
HTView supervision ensuring full traceability and NADCAP compliance
Swiss engineering for durability and long-term reliability