Nitriding process in gears - Gear Nomenclature
Nitriding is a common type of heat treatment process used for gears.
The nitriding process allows nitrogen to penetrate the steel's surface and harden it, thereby, improving the surface wear and corrosion resistance of the steel. When gas nitriding is performed, the steel is heated in an enclosed atmosphere filled with ammonia gas.
When compared to overall carburizing and quenching, the nitriding process offers the following notable differences :
- Longer processing times
- Lower processing temperatures (approx. 500°)
- Less deformation of the material
- A thinner hardened layer
- Quenching and Tempering is not required
The SACM 645 Steel is a nitriding steel, the presence of Aluminum, Chromium, and Molybdenum in the base steel makes it easy to nitride.
When gear teeth are nitrided, subsequent tooth grinding is not performed because of the loss of the thin hardened layer created by nitriding.