Abstract: To resolve the issues that phosphorus content in steel was over the upper limits, and the castability of liquid steel was poor, the influence of tapping temperature and tapping carbon content on phosphorus content in steel was investigated, the effect of ladle slag and RH operation on steel cleanliness was also investigated through thermodynamic calculation and production data analysis. After the optimized measures were taken, which included tapping temperature and carbon content decreased, slag modification agent added, tapping hole enlarged, RH deoxidation schema improved, BOF tapping time shortened by 0.9 min, the temperature drop during BOF tapping decreased by 15 ℃, the target ratio of phosphorus at BOF end increased from 87.1 % to 94.3 %, the ratio of oxygen-blowing at RH station decreased from 30.2 % to 14.3 %, and the continuously casting heat increased from 4 heats to above 8 heats in a single tundish.

Key words: SPHC steel, dephosphorization, castability, inclusion