Possibilities for desulphurization of an alloy steel in a VOD device while using chemical heating

Abstract

The paper describes the knowledge about and results of the experimental heats performed in an electric steel plant. The aim was to verify the possibilities of a controlled desulphurization of alloy steel in a VOD (Vacuum Oxygen Decarburization) device, particularly when using chemical heating through the OVD process (Oxygen Vacuum Deoxidation/Degassing), as well as the standard slag formers. Experimental procedures were used in the production of alloy tool steel. Both, the system of making the reducing slag and optimizing the composition of individual oxides in order to achieve the desired basicity, are complicated by the products of the chemical heating. Therefore, it was necessary to develop a new production technology that would eliminate such oxide products of chemical heating and, thus, the maximum degree of desulphurization could be achieved. The main principle of the technology is to create appropriate thermodynamic and kinetic conditions required for desulphurization. In particular, this concerns a low oxygen activity in the steel, the composition of refining slag, and an intense bath stirring with argon.