STUDY OF CLEANLINESS OF HIGH NITROGEN STEEL IN ESR
This paper compares inclusions in high nitrogen steel before and after ESR process,analyzes the influence of slag systems and total oxygen content in consumable ingots.The total oxygen content is reduced apparently during ESR process,which indicates good effects on removal of inclusions.In the experiment,it shows that different slag systems will affect the result of inclusions removal significantly; proper w(CaO/Al2O3)will reduce the level of inclusions and total oxygen content in ESR ingots.In ESR process,the type and chemical composition of inclusions have no difference when oxygen content in consumable ingots is different,which means O content in consumable ingots have no direct relationship with clea nliness of ESR ingots.In typical inclusions,w(MnO)/w(MnO+Al2O3)≈0.23~0.32.The total oxygen content of ESR ingots keeps between 20~30ppm when the oxygen contents in consumable ingots are diverse from 40 to 100ppm.Meanwhile,this paper studies desulfurization process of high nitrogen steel in ESR,analyzes the influence of slag systems and remelting rates on desulfurization efficiency.The results indicate that the average size and quantity of sulfide inclusion decrease after ESR process.The typical inclusion after ESR process is MnS+Al2O3.Slag system with proper CaO content has higher sulfur partition ratio,which leads to better desulfurization effect.The desulfurization rate changes greatly with different remelting rates,which indicates the kinetic parameter has more influence in desulfurization.The reason of this phenomenon is that the process of desulfurization can be considered as a non-equilibrium reaction,which differs with thermodynamic equilibrium.In kinetic study,it is founded that the desulfurization efficiency increases with higher remelting area,sulfur partition and lower remelting rate,which is different from experiment.The desulfurization efficiency decreases firstly and then recovers when remelting rate drops.The enrichment of sulfide in slag results in resulfurization in steel,which leads to lower desulfurization efficiency.
inclusion slag system total oxygen content cleanliness desulfurization
Tang Xuwei Zhu Rong
School of Metallurgy and Ecological Engineering,University of Science and Technology Beijing,Beijing,100083,China;Beijing key laboratory of special melting and preparation of high-end metal materials,Beijing,100083,China
国际会议
Energy Materials 2014(第一届能源材料国际会议)
西安
英文
343-349
2014-11-04（万方平台首次上网日期，不代表论文的发表时间）