Abstract: With scrap adding in multiple steps and BOF compensation heating at 210 t converter in Hunan Valin Lianyuan Iron &Steel Co.,Ltd, the hot metal consumption can be greatly reduced. Meanwhile, with denitrification capacity improved, over-blowing and reblowing reduced, and power system at low temperature in the early stage of IF station optimized, the calcium treatment eliminated, deoxidization process optimized, nitrogen pickup can be effectively reduced. With optimized ladle slag modification, TFe in the slag can be reduced, thus RH treatment time can be prolonged according to Al addition and oxygen blowing, and T.O content in tundish can be stabilized. Ultimately, the comprehensive hot metal consumption of high value added steel can be reduced to 820 kg/t, in addition, high value added steel with LF treatment can have 99.8 % of liquid steel with w(N)≤60×10-6, after RH treatment , liquid steel in tundish with w(T.O)≤28×10-6 can reach up to 95 %. Therefore, the steel output has been greatly increased, resulting in huge economic benefit.

Key words: low hot metal ratio, nitrogen control, cleanliness, steelmaking, practice