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Benefits
The benefits of vacuum carburizing affect not only the bottom line, but the environment. Unlike
carburization using solids or gas, the vacuum process doesn’t release any harmful chemicals. The
process is also faster than traditional methods because propane breaks down into its components so
quickly. Finally, the temperature needed to facilitate carburization is much lower when using a vacuum
furnace. This can save both time and money, since heating takes less energy and reaching the
appropriate temperature doesn’t take as much time.

Application
Carburized steel and iron have unique advantages over untreated metals, such as: less corrosion,
added strength and improved wear resistance. Like carburization using solids or plasma, the vacuum
method allows operators to determine the amount of carbon diffused into the metal by controlling
how long carburization occurs. The resulting carburized metal retains a flexible core while gaining a
more durable exterior.

3
Fig. 6. 2 Vacuum Carburization chamber

Liquid Carburization

Process description
Liquid carburizing is a process that is usually used for small and medium-sized parts. In the salt bath
the carbon to be diffused in the workpiece comes from a molten salt that is a mixture of sodium
cyanide (NaCN) and barium chloride (BaCl2) (Fig. 6. 3).
Carburizing in salt bath comes with the advantages of a flexible use, great temperature uniformity
around the part and it is quite easy to control. 4

Benefits
While metal alloy items are being submerged in this concoction, they come into contact with a
collection of carbon molecules. Generally, these carbon molecules will diffuse into the alloyed items
in a rapid manner, allowing for a hard case to form in just a short time.
Steels which have been liquid carburized typically possess high levels of carbon and low levels of
nitrogen.

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