中碳含硼钢氮含量的控制

Control of nitrogen content in boron-added medium carbon steel

采用氧氮分析仪分析湖南华菱涟源钢铁集团有限公司中碳含硼钢A36-LB在生产各工序中氮含量的变化,研究其吸氮原因。结果表明,转炉终点碳含量控制不稳定是造成该厂钢中氮含量波动的主要因素;虽然转炉终点碳含量高可以降低钢中的氮含量,但同时也会导致钢中磷含量增高;在LF精炼整个过程中钢水增氮约11×10-6,增氮较多,其中原材料增氮并不是主要原因,主要原因是电弧加热过程增氮较为严重;连铸工艺段增氮较少,保护浇铸较好。

With oxygen and nitrogen analyzer, the change in nitrogen co.ntent in boron-added medium carbon steel produced by Valin Lianyuan Iron and Steel Corporation Limited in each stage of the process was analyzed and so was the nitrogen absorption mechanism. The results show that the instable carbon content at BOF endpoint is the main factor for nitrogen content fluctuation. Though high carbon content at BOF endpoint may reduce the nitrogen content, it may lead to rephosphoration in BOF. Liquid steel nitrogen increase reaches 11×10^-6 in LF refining process, which is rather significant. ＇Yet the raw materials are not the main cause of nitrogen increase. Nitrogen increase mainly takes place during arc heating process. Nitrogen increase is comparatively small in CC process, which indicates protective casting is preferable.