Vacuum Degasser (VD/VTD/VOD)

Vacuum Degasser (VD) allows to degas and decarburize the melt and provides the best conditions for desulphurization and inclusions removal. During the VD treatment, the liquid steel ladle is placed in a vacuum tank that can be of stationary or movable design according to the specific layout needs. Vacuum condition is achieved with a vacuum pump system, formed by mechanical pumps or steam ejectors. In order to promote stirring, inert gas is injected through porous plugs. VD can be equipped with an additional oxygen lance (VD-OB process) and further benefits, such as forced decarburization or chemical heating, can be obtained. Tenova's VD can be designed as a twin unit, in order to maximize productivity without sacrificing process quality, using a single vacuum pump system. 

The VOD unit is mainly used for the production of stainless steel, it provides the most suitable condition for extensive decarburization and achievement of high-purity and cleanness. The unit is basically a tank degasser equipped with an oxygen lance, but specifically configured to withstand the heat load from an intense CO emission 

It is normally used for deep decarburization of high alloy steel grades, usually to remove carbon without affecting chromium content in the production of stainless steel grades. The VOD unit can be operated as the sole decarburization unit after the furnace (DUPLEX process) or as a refining stage after rough decarburization with an AOD unit (TRIPLEX process). 

All the units can be equipped with either mechanical pumps or steam ejectors.