Ferritic nitrocarburizing (FNC) is a thermochemical surface heat treatment used to harden the outer layers of steel components through the diffusion of nitrogen and carbon.
The process increases surface hardness, wear and galling resistance, fatigue resistance, reduces friction, and ensures high dimensional stability.
The treatment is applied to nitriding steels, tool steels, carbon steels, quenched and tempered steels, and cast irons.
CHARACTERISTICS
Type of treatment:
Thermochemical surface heat treatment
Surface appearance:
Uniform and compact surface with a characteristic grey coloration.
Case depth:
Effective case depth is defined according to hardness penetration classes (NcE – UNI 10931:2001), typically ranging from 0.1 to 0.6 mm.
Process description:
the component is heated to temperatures between 550 and 600°C (ferritic range) and held in an ammonia atmosphere.
Ammonia dissociation releases nascent nitrogen, which diffuses into the steel surface and reacts with alloying elements forming nitrides.
In addition, hydrocarbons are introduced to provide carbon, contributing to the formation of the treated surface layer.
ADVANTAGES
- Limited component distortion
- High resistance to abrasive and adhesive wear
- Increased fatigue resistance
PROCESSABLE MATERIALS
- carbon steels (C15, C20, C45)
- alloy construction steels (16MnCr5, 20MnCr5, 42CrMo4)