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Liquid Nitriding Process

Basic Process Steps for Liquid Nitriding:

CLIN Process Steps Scope Description
Degreasing/Rinsing Remove oils, and other particulates from the surfaces of the parts
Preheating Maintain a stable temperature in the nitrocarburizing melt
Nitrocarburizing Nitride layer formation on component surface. Using HEF’s ARCOR® and MELONITE® & TUFFTRIDE® / (TENIFER®) Nitriding salts The hard nitride layer provides wear resistance. The diffusion region underneath the nitride layer provides improved fatigue life
Oxidizing* Oxide layer formation on component surface. Using HEF’s Oxynit® and other trademarked Oxidizing salts Oxynit® is a post-nitrocarburizing molten salt bath treatment that provides added corrosion protection by oxidizing the porous zone of the iron nitride compound layer into stable iron oxides (Fe3O4) – also called magnetite. Oxide layer also provides a black aesthetic appearance.
Cooling/Cleaning Remove salt from the surface of the parts
Mechanical finishing* Smooth surface, low roughness (no lower than before treatment), friction properties HEF expertise:
Blast finishing
Mass finishing
Centerless polishing
Surface Impregnation* Additional corrosion resistance;
improved run-in behavior;
deep-black appearance
HEF impregnation using:
Corolac® (dry appearance)
Corofluide® (oily appearance)

The LN process is carried out in equipment manufactured by HEF and customized to the nature of the applications under consideration – the size and shape of components to be nitrided; the throughput rate required; process steps required to achieve the desired nitriding specifications; and environmental considerations. A schematic view of a typical ARCOR® process line is shown below:

ARCOR® process line

These CLIN process lines can be fully/partially enclosed or have an open configuration as shown below:

CLIN process lines