METHOD OF LANCE INSTALLATION IN POSITION OF MELT BLOWING IN LADLE Russian patent published in 1998 - IPC

FIELD: metallurgy, in particular, methods of control of conditions of melt blowing in ladles with gases, for instance, with nitrogen or argon. SUBSTANCE: method includes supply of inert gas with flow rate used in blowing. Lance is lowered into melt at preset speed with simultaneous supply of inert gas. Lance motion is discontinued in position of blowing at preset depth on the basis of analysis of dynamics of pressure-versus-time relationship. Found on smoothed relationship curve in correspondence with the process rate is point of curve knee corresponding to the moment of touching of melt surface with nozzle. Time interval required for reaching the position of blowing by lance is calculated by ratio of preset depth of lance immersion into melt to the known speed of lance lowering. Upon elapse of this time interval, lowering of lance is discontinued. During the entire period of lance installation to blowing position, gas nominal flow rate is maintained. EFFECT: higher accuracy of lance installation to blowing position irrespective of melt level in ladle, length of lance and degree of nozzle cross-section reduction due to deposition of metal. 2 dwg