ФИЗИКО-ХИМИЧЕСКИЕ ХАРАКТЕРИСТИКИ, ПОЛУЧЕНИЕ И ПРИМЕНЕНИЕ КОМПЛЕКСНЫХ БОРСОДЕРЖАЩИХ ФЕРРОСПЛАВОВ

The  data  on  the  feasibility  of  production  and  application  of  complex  ferroalloys  from  the  standpoint  of  manufacturing  technology,  the  used  raw  materials  and  the  interaction  with  the  steel  are  provided. The production need of complex ferroalloys has been validated; the main principles of determination of ferroalloys chemical  composition  are  shown.  The  rational  composition  of  complex  fer-roalloys (ferro silicon manganese with boron, ferrosilicon with boron,  ferrosilicon manganese with boron and chrome) has been determined  based on the research of their physicochemical properties and their  specific  interaction  with  basic  melt.  The  comparison  of  characteristics  of  complex  boron-bearing  ferroalloys  (melting  temperatures,  density, melting time of ferroalloys in melt, etc.) was made against  the most used ferroboron and their advantages were shown. It was  noted that the complex boron-bearing ferroalloys must have active  element (Si, Al, Ti), because they promote binding oxygen and nitrogen from steel melt in firm compounds, and the compounds prevent  interaction  of  active  element  with  boron. The  boron  concentration  in ferroalloy must be 0.7–2.0  %, because it increases the volume of  complex  boron-bearing  ferroalloy  as  consequence  increase  of  reliability and stability of boron absorption. The study of oxidation of  boron-bearing ferroalloy has shown that ferrosilicon with boron are  far less oxidative (4–7 times) at higher temperatures (1430–1570  °С)  than ferroboron. The results have been given for manufacturing and  application of boron ferrosilicon in steel production. The recovery  rate of boron has been studied. The usage of ferrosilicon with boron  provided high recovery rate of boron in range of 77.8–96.3  % (average 86.6  %), without changes in present techno  logy of steel deoxidation with ferrosilicon. The concentration of boron in metal at ladle  treatment is 0.0021–0.0027  % and the concentration of boron is not  less than 0.0020  % at casting. It was found that the entering of boron  with the help of ferrosilicon manganese with boron provides increase  of recovery rate of boron in 1,6 times (in average from 48 to 77  %)  relative to ferroboron usage.