Abstract: In the light of problems of smelting ultra-low phosphorus steel (%/： <0. 03C、<0. 01 OP、<0. 015S、< 0.06Mn、vO. 02Cr、<0.02Ni), the lower liquid temperature at 90 t BOF tapping and serious overoxidation of liquid, led to heating refining by LF, are tested and studied by process optimization. The results show that during BOF (0. 018% - 0. 025% P) tapping process by adding lime and refining slag to produce slag with binary alkalinity 7 and P2O5 <0.5%, the dephosphorization rate of liquid in ladle reaches up to 75%, the phosphorus content of finished products is less than 0.010%, the smelting time is shortened by 3 ~ 4 min. At the same time, the dephosphorization rate of ladle decreases with the increase of liquid steel temperature at the end of converter blowing, the BOF optimum end-point temperature is between 1 630 °C and 1 655 °C. By adopting ladle dephosphorization technology, the smelting process of ultra-low phosphorus steel is shortened to converter blowing—►RH treatment—►continuous casting, and the LF refining process is omitted.

Key words: Ultra?Low Phosphorus Steel, Ladle, Slag, Dephosphorization in BOF Tapping Process

摘要： 对钢厂采用90 t转炉冶炼超低磷钢(%/:<0.03C,<0.010P,<0.015S,<0.06Mn,<0.02Cr,<0.02Ni),转炉终点钢液温度偏低、过氧化严重，需经过LF升温精炼等问题，进行了工艺优化试验研究，结果表明：转炉(0.018%～0.025%P)出钢过程中使用石灰和精炼渣，形成二元碱度为7、<0.5%P2O5炉渣，可使钢包钢水脱磷率达到75%,成品磷含量低于0.010%,冶炼时间缩短3～4 min。同时，转炉吹炼终点钢液温度升高，钢包脱磷率呈降低趋势，转炉最佳终点温度为1630～1655℃。通过采用钢包精炼脱磷技术，超低磷钢冶炼流程缩短为转炉吹炼→RH处理→连铸，减少LF精炼工序。

关键词: 超低磷钢, 钢包, 炉渣, 转炉出钢过程脱磷