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Salt Bath Nitriding / Liquid Nitriding / |
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Salt bath nitriding / liquid nitriding* is a subcritical surface enhancement
process with the longest track record of success of 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.
In a liquid nitriding bath, nitrogen-bearing salts produce a controlled
and highly uniform release of nitrogen at the interface of the workpiece.
Nitrogen diffuses into, and chemically combines with, nitride-forming
elements in the metal, producing, through catalytic reaction, a tough,
ductile compound layer with exceptional engineering and wear properties.
This compound layer has wear properties that are 200% to 1000%
greater than the original material, and greatly enhanced resistance
to corrosion, and galling.
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 a critical fourth benefit of salt bath nitriding:
substantial enhancement of fatigue strength, typically 20% to 100%.
Salt bath nitriding / liquid nitriding is a highly active case hardening process;
it is
more intense, and more efficient than gas nitriding, or ion nitriding.
Salt bath nitriding / liquid nitriding is performed following heat treating and
finish machining. Dimensional stability of processed parts is not changed,
and core properties are uncompromised, providing heat treat temperatures
were higher than the salt bath nitriding solution (typically 1060-1075°F).
Parts that have been processed in a salt bath nitriding / liquid nitriding
solution can be quenched in water, air, or oil.
HEF USA is North America’s leader in the application of salt bath
nitriding / liquid nitriding for case hardening. Arcor®, Sursulf™,
Melonite®, QPQ™, Tufftride, and their predecessor, Tenifer/TF1 are the
leading choices for manufacturers who require highly consistent
case hardening for high volumes of critical parts.
Our mission is to demonstrate the diverse range of automotive, aerospace,
agricultural, mining, off-highway and oil patch components whose properties,
service life, and life cycle costs can be improved using these
time-proven case hardening processes.
* Salt bath nitriding, liquid nitriding and ferritic nitrocarburizing all refer to the same process.
