Ning Zhoushao, Li Changrong, Wang Jie, Zhai Yongqiang, Xiong Xingqiang, Chen Lu
College of Materials and Metallurgy, Guizhou University, Guiyang 550025, China.
Guizhou Province Key Laboratory of Metallurgical and Process Energy Saving, Guiyang 550025, China.
Materials (Basel). 2023 Jul 18;16(14):5070. doi: 10.3390/ma16145070.
In this paper, an experimental protocol of adding rare earth lanthanum (La) was used to refine and modify inclusions (AlO) in aluminum-deoxidized steel. An optical microscope (OM), a scanning electron microscope (SEM), and an energy dispersive spectrometer (EDS) were used to study the impact of size distribution, number density, distribution uniformity, interfacial distance, area density, and so on of rare earth La on high-carbon hard wire steel inclusions. As indicated by the findings when the addition amount of La is 0.063%, the refining and homogenizing effect of AlO inclusions in steel is the best. The average diameter of the inclusions is 1.75 μm, the uniformity is 0.84, the proportion of the interfacial spacing greater than 10 μm is 48.4%, and the area density of inclusions is set at 0.014. Based on classical thermodynamics and Factsage software, the effect of La activity on inclusion formation was computed. As indicated by the findings, the addition of rare earth La mainly combines with O and S in the liquid steel, and the La-containing inclusions wrap around the AlO inclusions, hindering the AlO inclusions. Through the evolution of inclusions during solidification, the modification of AlO inclusions via rare earth La and the types of inclusions are discussed. The experimental results and theoretical calculations verify that the optimal treatment plan is to add 0.063% La.
本文采用添加稀土镧（La）的实验方案对铝脱氧钢中的夹杂物（AlO）进行细化和变质处理。利用光学显微镜（OM）、扫描电子显微镜（SEM）和能谱仪（EDS）研究了稀土La的尺寸分布、数量密度、分布均匀性、界面间距、面积密度等对高碳硬线钢夹杂物的影响。研究结果表明，当La的添加量为0.063%时，钢中AlO夹杂物的细化和均匀化效果最佳。夹杂物的平均直径为1.75μm，均匀性为0.84，界面间距大于l0μm的比例为48.4%，夹杂物的面积密度设定为0.014。基于经典热力学和Factsage软件，计算了La活度对夹杂物形成的影响。研究结果表明，稀土La的添加主要与钢液中的O和S结合，含La夹杂物包裹在AlO夹杂物周围，对AlO夹杂物起到阻碍作用。通过凝固过程中夹杂物的演变，探讨了稀土La对AlO夹杂物的变质作用及夹杂物类型。实验结果和理论计算验证了最佳处理方案为添加0.063%的La。
