石钢转炉钢水氮含量研究与控制

Study on the nitrogen content of molten steel in converter and its control

针对生产齿轮系列钢氮含量超标情况,重点对生产齿轮钢种转炉冶炼过程进行了跟踪和取样对比分析,实践得出:通过控制底吹氮氩切换时间为9.5 min,减少补吹次数,转炉终点氮含量可稳定控制在21 mg/L;采用出钢弱脱氧的生产方式,减少出钢时间,可有效降低出钢脱氧合金化的吸氮量;炉后底吹流量120 L/min,既可以减少钢液裸露,又可以保证良好的软吹效果。采用上述方式后,达到了降低和稳定转炉钢水氮含量的效果。

In view of the situation that the nitrogen content of gear series steel exceeds normal standards,investigation and sampling comparative analysis are conducted upon the smelting process of gear steel in converter.The results show that by controlling the switching time of bottom blowing nitrogen and argon to be 9.5 min and reducing the times of supplementary blowing,the nitrogen content at the end of converter can stably stay at 21mg/L.By adopting the production mode of weak deoxidization in tapping,reducing tapping time,the nitrogen absorption of deoxidization alloying in tapping can be effectively reduced.The bottom blowing flow after furnace is 120 L/min,which can not only reduce molten steel exposure,but also ensures favorable soft blowing.After adopting the above methods,the nitrogen content of molten steel in converter is reduced and stabilized.