Heat is typically required to change the formation and appearance of metals. However, as these heated metals react with air, the said interaction would manifest numerous unwanted changes to the materials such as discolouration, scale, or contamination. The effects of the interaction with air are brought by the oxidation process, which should be avoided to achieve desired metal properties.
One great way to avoid the oxidation process is through vacuum heat treatment. This specific treatment places the metal material in a high-temperature vacuum furnace to effectively remove any reactive element. Additionally, this tightly sealed furnace heats the metal material to the most optimal temperature for it to obtain the intended properties. The soak time of the heated metal material will then depend on the needs of the part and the type of metal that is used. It would typically take around 3 to 24 hours for the whole material to be processed, ensuring its uniformity and repeatability are intact.
Vacuum heat treatment is utilised by a lot of industries due to the following advantages:
Eliminates Contact with Elements
One advantage of vacuum heat treatment is that it eliminates any contact of the metal material to various surrounding elements. The ability of this treatment to isolate the material from oxygen prevents it from having a rough surface, losing metallic lustre, and obtaining soft spots and cracks. The strength of the metal material, as well as its mechanical properties, are also preserved when subjected under vacuum heat treatment since any oxidation, decarburisation, and other processes are avoided.
Improves Mechanical Properties
Another reason why vacuum heat treatment can improve the mechanical properties of a metal is due to its ability to reduce hydrogen to the material. Hydrogen can be dangerous to metals. Fortunately, vacuum heat treatment can reduce the hydrogen content of the material, leading to a significant improvement over its plasticity, toughness, and fatigue strength. The vacuum furnace can readily get rid of the oxides and any free oxygen formed during the whole heating process.
Maintains High Thermal Efficiency
The whole process of vacuum heat treatment has high thermal efficiency, which is very helpful in maintaining the stability and repeatability of the metal from being processed. The high thermal efficiency of the treatment also makes it possible for the material to undergo rapid heating and cooling, preventing it from undergoing oxidation, decarbonisation, and carburisation. Degreasing and degassing are likewise possible with vacuum heat treatment without causing any harm and pollution to the surroundings.
Reduces Workpiece Volatility
Metal materials that are processed with vacuum heat treatment are expected to obtain reduced workpiece volatility. This specific characteristic allows the material to retain its features and properties even if they will be formed and processed again.
All these advantages allow the vacuum heat treatment to be pivotal for industries that strictly rely on metal hardening process. Without vacuum heat treatment, oxidation can still be a huge problem for most industries, making the whole metal processing difficult.