How Does Vacuum Heat Treatment Work?

13 October 2021

Metal workpieces often undergo numerous processes to obtain substantial changes in their properties. One of these processes is the heat treatment process.

Heat treatment is a term used to describe activities that can alter the physical properties of a metal workpiece. This specific process typically involves heating or cooling in introducing changes to the involved part or component. Some properties that are affected by the heat treatment process include hardness, ductility, strength, toughness, and resistance to elements.

One great thing about the heat treatment process is that it can be done in numerous ways. It can even be done in various locations, ensuring that a workpiece can obtain its needed changes.

Issues with Heat-Treating Metal Workpieces

Before its processing, a metal workpiece is often exposed to various surrounding elements such as oxygen, carbon dioxide, and moisture. And with prolonged exposure to these elements, the metal workpiece may obtain changes and reactions, especially if it is processed with intense heat.

Now, to minimise undesirable reactions, professionals would often eliminate the source of the reactive elements from the heat-treating environment. One way of doing this is to replace the air in the heat-treating chamber with nitrogen, argon, or other gas combinations. Another way would be the exposure of the metal workpiece in a non-reactive molten salt bath. These processes may deter most of the undesirable reactions from the elements, but the workpiece would still contain low levels of impurities.

Vacuum Heat Treatment is the Key Solution

Vacuum heat treatment, fortunately, can remove most of the reactive elements from the heat-treating environment or heat-treating chamber. With the help of a vacuum pumping system, it can get rid of most air elements inside the heat-treating chamber that cause undesirable reactions and discolouration to the workpiece. Sometimes, an oil diffusion pump is installed alongside the pump system so that it can further eliminate elements and allow more sensitive metal workpieces to be heat treated.

The furnaces used for the vacuum heat treatment, however, can only be effective if they are maintained regularly. Without proper maintenance, they might develop some leaks, which can only lead to contamination during the heat treatment process.

The Processes of Vacuum Heat Treatment

Vacuum heat treatment starts with the positioning of the workpieces in a special chamber. With a vacuum pumping system and other related components, the elements inside the chamber will be removed and replaced with argon gas or other similar elements. Once these steps are done, the chamber will be subsequently heated up to as much as 1,300 degrees Celsius before lowering it for some time. The entire cycle of the vacuum heat treatment may take three hours to one day, depending on the needed material.

A fully maintained vacuum heat treatment furnace can easily produce workpieces with boosted strength and improved thermal efficiency. It can likewise avoid oxidation, decarburisation, and carburisation.

To know more about this process, you can call us at Alpha Detroit Heat Treatment.


Benefits of vacuum heat treatment. Jones Metal Products. (2020, June 11).

MetalTek International. (2021, June 2). Heat Treatment | Metal Processing. MetalTek.

VAC AERO International. (2019, May 15). Why Heat Treat in a Vacuum?Vacaero.

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