铝镇静钢氮含量控制分析

Analysis of nitrogen content control in Al-killed steel

在炼钢过程中,将成品氮质量分数稳定控制在0.003%以下存在一定难度。对铝镇静钢而言,常规生产流程为BOF-RH-CC,增氮和脱氮在每个工艺环节都可能会发生。本研究进行了9炉工业试验以研究冶炼全过程中氮含量的变化。结果表明,转炉冶炼终点钢中氮含量随碳氧积的增加而增加,而碳氧积反映了转炉底吹搅拌效果。出钢过程发生了增氮现象,合金化时间越长,转炉终点碳含量越低,出钢口的使用炉数越多,增氮量越大。对于RH过程中脱氮行为,RH浸渍管越新,脱氮越多。根据所得结论,提出了控制钢中氮含量的可行措施。

In the process of steelmaking,it is difficult to control the nitrogen mass fraction of finished product below 0.003%.For the production of Al-killed steel,the general manufacture routine is BOF-RH-CC,and nitrogen absorption and desorption could happen in every process.In order to study the change of nitrogen content in the whole smelting process,nine industrial tests were carried out.The results show that the nitrogen content in steel at the steelmaking end-point increases with the increase of carbon and oxygen accumulation,which reflects the stirring effect of bottom blowing.During tapping,nitrogen absorption occurred,and the longer the alloying time is,the lower the carbon content at the steelmaking end-point is.The more the number of taps used,the greater the amount of nitrogen absorption increased.For the nitrogen desorption behavior during RH process,the newer the RH immersed nozzle is,the more nitrogen desorption occurs.According to the conclusion,the feasible measures to control the nitrogen content in steel are proposed.