Salt bath nitriding / liquid nitriding is a subcritical surface enhancement process holding the longest track record of success over any case hardening technology. It is widely used to enhance the performance of titanium, chromium, and aluminum alloyed steels, as well as low alloy materials, and stainless steels. It is more intense, and more efficient than gas nitriding, or ion nitriding.

Salt bath nitriding / liquid nitriding advantages include active case hardening process (compound zone), additional lubricity, improved corrosion resistance, as well as improved aesthetics. Dimensional stability of processed parts does not change and core properties are uncompromised.

Salt bath nitriding / liquid nitriding can be performed on thru hardened steel. This yields the benefits of thru hardening in the addition to a harder surface. This can be up to 75Rc, depending on the material.

Subjacent to the compound zone is another distinctive region, the diffusion zone. This evolves from progressive diffusion of the nitrogen, and consists of a solid solution of nitrogen in the base material. The diffusion zone contributes another critical benefit of salt bath nitriding: substantial enhancement of fatigue strength, typically between 20% to 100%.