Characteristics and advantages of ladle vacuuming of steel using the VDF/VODF process

Abstract

Traditional techniques for vacuum refining of ladle steel using the well-known VD/VOD processes are now seeing widespread use at steel smelting enterprises, but have several deficiencies alongside the advantages: The need for the steel pouring ladle to have a high freeboard; insufficient metal mixing rate; overheating and subsequent premature failure of the ladle during forced decarburization (VOD process). In order to minimize and eliminate these deficiencies, we suggest a new process (VDF/VODF) and related equipment, which has undergone industrial-scale testing. The stirring power per unit mass was shown to increase by 25-30%, with an increase of up to 15% in the mass of metal being processed, and a decrease in the amount of time required for vacuum treatment. We present various mathematical relationships that enable the increase in mixing rate to be estimated. Using a reaction chamber that also plays the role of a heat shield substantially reduces the thermal load on the upper collar of the steel pouring ladle.