Vacuum degassing furnaces have undergone years of development, resulting in various technological approaches to adapt to different production scales and process requirements.
1 VD/VOD Ladle Vacuum Degassing Furnaces
Vacuum Degassing (VD) furnaces and Vacuum Oxygen Decarburization (VOD) furnaces are widely used vacuum refining equipment in large steel enterprises. Their characteristic is the transfer of molten steel from electric arc furnaces or converters to ladles, which are then suspended into vacuum tanks for processing. VD furnaces primarily perform degassing, deoxidation, desulfurization, and composition fine-tuning; VOD furnaces, based on VD, add top-blown oxygen functionality and can be used for decarburization refining of ultra-low carbon steels such as stainless steel.
These types of equipment have large processing capacities, typically 50-300 tons, suitable for large-scale production. The 100t VD furnace used by Hangzhou Steel Changxing Electric Arc Furnace Steelmaking Co., Ltd., designed by Voestalpine, represented the international advanced level at the time, achieving a steel purity of over 99.99% after processing.
2 VID/IMVD Induction Melting Vacuum Degassing Furnace
VID (Vacuum Induction Degassing) furnaces and IMVD (Induction Melting Vacuum Degassing) furnaces are compact pieces of equipment developed for small- to medium-batch, multi-variety, high-quality alloy production, with a maximum design capacity of up to 30 tons.
A key feature of these furnaces is their integration of melting, refining, and casting into a single unit, eliminating the temperature loss and secondary contamination risks associated with transferring molten steel between different equipment. The workflow is as follows: induction melting of solid metal material in atmospheric conditions → sealing the furnace lid and evacuating the vacuum → refining and degassing under vacuum → casting under a vacuum or protective atmosphere. Throughout the process, the induction furnace is continuously heated to compensate for temperature losses.
VID furnaces are particularly suitable for refining high-end materials such as tool steel, high-speed steel, bearing steel, nickel-based alloys, and cobalt-based alloys. Equipment manufacturers have also developed various variants, such as “VID Pro” (protective atmosphere casting) and “VID Oxy” (oxygen blowing decarburization), to meet different process requirements.
3 Vacuum Degassing Device for Molten Aluminum
Degassing is also required in aluminum alloy smelting to remove hydrogen and oxide inclusions. The vacuum degassing device for molten aluminum combines rotary jet cleaning with vacuum treatment. The equipment consists of a degassing tank and a vacuum degassing chamber, with a graphite rotor installed at the bottom of the chamber. Under vacuum negative pressure, the aluminum liquid level rises, the rotor rotates and sprays inert gas, forming numerous microbubbles that fully contact the molten aluminum, efficiently removing hydrogen and adsorbing inclusions.
This type of equipment is widely used in the production of aluminum plates, strips, and foils, as well as in aluminum alloy die casting and gravity casting, significantly reducing porosity defects in castings and improving product yield.