The oxygen content in concasting billet has been controlled less than 20×10-⁶ in condition of non-vacuum treatment with 55 t LD-60 t LF melting flow sheet at Shijiazhuang Iron and Steel by the operation measures such as controlling LD blowing end-point carbon:low carbon steel 0.08%~0. 10%C;medium carbon steel 0. 10%~0. 15%C and high carbon steel ≥0.20% C
strengthening pre-deoxidation at steel tapping of LD
controlling slag tapping rate up to 98%
controlling Als 0.020%~0.035% during LF refining
to ensure refining(FeO)≤0.5%
feeding CaSi wire
50~80 L/ min soft blowing argon time ≥7 min
protective casting in whole process
using high efficiency holding and absorbing slag agent