CAS底吹氮气冶炼高氮钢的研究与应用

Practice of Nitrogen Alloying for High-Nitrogen Steel by Bottom-blowing Gas in CAS Process

通过CAS底吹氮气冶炼高氮钢具有低成本的显著优势。但与RH增氮相比,如现场操作表明工艺参数控制不当,CAS底吹氮气会出现增氮控制不稳定的问题。为解决该问题,本文研究了钢水温度、吹氮时间、氮气压力、氮气流量对钢水增氮的影响。结果表明:钢水温度越高,增氮速率越快;吹氮时间越长,钢水增氮越多;氮气压力和流量越大,钢水增氮速率越快。300 t工业试验表明:在氮气压力为1.7 MPa、1873 K下,500~600 L/min底吹氮气流量下,增氮速率稳定,钢水中的氮含量控制准确度从50%提高到95%。

It was proved that the most low-cost way for nitrogen alloying is by bottom-blowing.However,compared to RH process,bottom-blowing way is with its disadvantage of unsteady nitrogen yield during the process.To finalize the problem,the paper was involved how to stabilize the process by studying the temperature of steel,gas-blowing time,gas pressure and gas flow,which are supposed to have big influences.The results show the curves of increasing nitrogen content in steel with higher temperature,longer gas-blowing time,higher gas pressure and increasing gas flow.It was also concluded from industrial trials that the nitrogen content hit rate increases from 50%to 95%with the conditions of 1873 K,500~600 NL/min of flow and 1.7 MPa of nitrogen gas pressure.