关键词: 100t BOF-LF-CC流程, 10B21钢, 增硅, 钢液可浇性, 角裂

Abstract: According to the issues for the steel 10B21 (/% : 0.19-0.22C, ≤0.08Si, 0.8-1.0Mn, ≤0.020P, ≤0.020S, 0.010-0.040Al, 0.001-0.005B) during steelmaking process including silicon content in liquid going beyond the limit of standard, poor castability and exiting cracked comer of cast billet , with analysis on production data and inclusions in steel, and cast billet macro-examination, it is obtained that after LF white slagging, the SiO₂ in slag is reduced by Al led to [Si] going beyond the limit； the castability of steel 10B21 decreases by Al₂O₃ in liquid depositing in nozzle, and during casting solidification process the boron nitride and oxide precipitate at grain boundary causing cast billet cracked comer. With using the process measures including increasing BOF end [C] to 0.10%-0.14% , controlling tapping liquid temperature 1640-1660℃,decreasing BOF aluminium iron adding amount from 1.82 kg/t to 1.36 kg/t, decreasing LF refining aluminium iron adding amount from 2.8 to 1.6 kg/t, increasing feeding calcium amount from 1.23 kg/t to 2.05 kg/t, adding micro fixed nitrogen element Ti and optimizing casting process, the ratio of [Si] ≤0.08% increases from 65.62% to 89.50% , single tundish continuous-continuous casting heats in crease from 4 heats to 12 heats and the casting bloom cracked comer is effectively controlled , and the yield of qualified cast billet increases from 88.23% to 97.44%.

Key words: 100 t BOF-LF-GC Flowsheet, Steel 10B21, Silicon Increment, Liquid Steel Castability, Cracked Comer