Ow pressure vacuum carburizing has expanded to encompass the latest demands of the aerospace, automotive and industrial markets, particularly in the areas. HPGQ or oil quench single - and doublechamber vacuum carburizing furnances. Vacuum carburizing low-pressure processes using methane (CH4) technology requires higher temperatures and pressures up to mbar ( torr).


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Of course, the carburizing action at the point of contact with the component must be taken into consideration. The grain growth of case-hardening steels also does not permit such high temperatures vacuum carburizing a long period of time. The vacuum furnace offers a pearlitizing treatment vacuum carburizing refine the grain.

Distortion Vacuum carburizing with gas quenching offers a potential for reduced parts distortion.


A large number of experiments, conducted vacuum carburizing on transmission parts, have shown that the scatter of the dimensional and shape changes after gas quenching is narrower than vacuum carburizing oil quenching.

For example, a clutch body O.


The study evaluated so clutch bodies after case hardening in the vacuum furnace quenching with helium at 20 bar and, for comparison, 50 others were evaluated after case hardening in the vacuum carburizing furnace oil quenching.

The radial run-out of the clutch bodies was measured in the soft and hard states. The difference is illustrated in Figure V. Advantages Case hardening in vacuum heat-treatment systems with gas quenching offers the user many advantages in comparison to conventional protective-gas carburizing with oil quenching.

Parts are clean and dry after treatment requiring no washers vacuum carburizing management or disposal of liquid waste. Leidenfrost phenomenon is avoided and with more uniform quenching, distortion is minimized.

As a protective atmosphere, vacuum can prevent case oxidation and eliminate toxic off-gases. The vacuum carburizing process also provides a high carbon mass flow rate with low consumption of carburizing gas. With regard to productivity, the vacuum process can be integrated into a production line without the burdening requirements for fire-protection and fire-extinguishing systems, excessive heat removal to the surroundings, or extensive exhaust gas handling.

The case-hardening steel can be carburized up to its limit of solubility in the surface layer without any sooting occurring.

Vacuum Carburizing FAQ: All you would like to know

These two factors result in an enormously shortened process duration. The carburization results are comparable with those of the protective-gas process with regard to case depth, case carbon content, and surface hardness.

The vacuum carburizing system is a captive cooler that uses biodegradable glycol to keep things running cool. Simply put there are no environmental side effects to vacuum carburizing that still exist in many other heat treat processes.

How much vacuum carburizing stock do I need to leave on for grinding after the parts are vacuum carburized?

Vacuum carburizing and gas quenching can offer the distinct advantage of creating a nearly virtual finished part that needs very little grinding or cleaning. By working closely with our customers and with proper recipe development, much of vacuum carburizing post heat treat grinding stock, if not all of it, can be left off.

This can offer vacuum carburizing savings in overall post operation machining costs.


The short answer is yes. There is no way to get around the fact that when steel is heated up to very high temperatures and rapidly quenched, the material does distort to some extent. Vacuum carburizing, the extent of vacuum carburizing can be controlled by choosing the most efficient heat treat processes available.

In an uncontrolled air atmosphere and by using separate quench methods, distortion can be excessive. Under vacuum with the addition of internal High pressure up to 20 Bar gas quenching, we see a very consistent or reproducible amount of movement per lot or load.

This allows the manufacturer to plan all subsequent operations based on the knowledge that they are going to get a consistent part back.