2018 Volume 58 Issue 11 Pages 2032-2041
A novel Rb2O-containing synthetic LF refining slag has been developed in order to produce ultraclean C96V saw wire steel. In addition, the thermodynamic and kinetics mechanism of Rb2O on inclusion removal have been discussed fully. The results indicated that (1) Rb2O additions (≤10.00 wt%) seems to significantly enhance inclusion removal in steel melts. ① The average diameter of nonmetallic inclusions decreased significantly with the Rb2O addition in synthetic LF refining slag increasing. In particular, the diameter of most of inclusions was less than 3.0 × 10−6 m (3.0 µm) when Rb2O addition was 10.00 wt% ② The number of nonmetallic inclusions decreased sharply with the content of Rb2O in synthetic LF refining slag raising. ③ Both of the MnO–SiO2–Al2O3, CaO–SiO2–Al2O3 inclusions system mainly concentrated in the low melting point zone. (2) For the 15.00 wt% Rb2O-containing synthetic LF refining slag, not only the average diameter of inclusion increases slightly with reaction times increasing, but also the number. This is due to the fact that, the effect of Rb2O on the ability of refining slag to absorb inclusions is a double-edged sword: On the one hand, Rb2O addition would promote the thermodynamic conditions of inclusion removal, then, inclusions would enter the slag spontaneously easier. On the other hand, Rb2O addition could also exacerbate the kinetic conditions of inclusion removal by increasing the viscosity of slag at the same time.