非脱磷铁水在210t转炉高拉碳法冶炼高碳钢的生产工艺研究及实践

Study and Application of Catch Carbon to Produce High-Carbon Steel on 210 t BOF

采用前期双渣法、高拉补吹法在210 t转炉上开展了高拉碳法冶炼高碳钢的大工业试验,出钢碳质量分数为0.04%-0.07%。对于非脱磷铁水冶炼高碳钢,脱磷是高碳出钢的关键环节。试验结果表明：前期双渣法5 min内可将铁水中磷的质量分数由0.078%-0.094%降至0.027%-0.038%;高拉补吹法在碳的质量分数为0.8%-1.1%时拉碳,钢水中磷的质量分数为0.014%-0.023%;这2种方法出钢钢水磷含量低,出钢后钢水回磷少,可以实现出钢时碳的质量分数为0.4%-0.7%,满足成品磷的质量分数小于0.015%。高碳条件下炉渣的高氧化性利于钢中磷的去除,实现高碳出钢。高拉碳法工业应用后,高碳钢平均出钢碳的质量分数由原来的0.22%提高到0.40%左右,钢中全氧的质量分数平均降低1.6×10^-6,氮的质量分数平均降低5.1×10^-6。

Catch carbon is used to produce high carbon steel with double slag and catch carbon and re-blowing practice. Phosphorus removal is very crucial for refining non-dephosphorized hot metal to produce high carbon steel. The phosphorus content in hot metal was decreased from 0. 078%-0. 094% to 0. 027%-0. 038% in 5 minutes using double slag method. When the carbon content of 0. 8%-1. 1% in steel and phosphorus content could be reduced to 0. 014%-0. 023% using catch carbon and re-blowing method. Thus 0.4%-0. 7% tapping carbon content and less than 0. 015 % phosphorus in final product could be reached by using these two methods together for theirs lower tap- ping phosphorus due to less rephosphorization after tapping. The high oxidizahility of ths slag at high carbon content in steel benefits phosphorus removal. After the application of this method, the average tapping content of carbon was increased from 0. 22% to 0.4%, the total oxygen content and nitrogen content decreased by 1.6 × 10^-6 and 5.1 ×10^-6 respectively in average.