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对国内一钢厂EAF→LF→VD→CC工艺生产的高品质GCr15轴承钢进行系统取样,针对DS类非金属夹杂物随机性强的特点,利用能够进行大面积试样检测的ASPEX自动扫描电镜分析统计钢中非金属夹杂物的成分、尺寸、数量等信息.研究发现:GCr15轴承钢冶炼过程中非金属夹杂物主要为MgO-Al_2O_3-CaO复合夹杂物和Mn S,同时有少量的SiO_2-Al_2O_3和MgO-Al_2O_3复合夹杂物;夹杂物尺寸主要集中在3~8μm,并有少量DS类夹杂物出现且尺寸范围波动很大,最大可以达70μm以上,形貌为圆形或近似圆形;VD有较强的去除夹杂物功能,经过VD真空精炼,夹杂物中CaO含量有增加趋势;吊包至铸坯过程,夹杂物成分向Al_2O_3含量增多的区域移动,最终轴承钢铸坯中夹杂物成分位于高Al_2O_3含量(≥80%),少量MgO(<20%)和低CaO(<5%)的区域;DS夹杂物的生成和去除具有较强的随机性.
A high-quality GCr15 bearing steel produced by a steel mill EAF → LF → VD → CC process was systematically sampled. According to the characteristics of strong randomness of non-metallic inclusions of DS type, ASPEX automatic scanning electron microscope The content, size and quantity of non-metallic inclusions in steel are analyzed.The results show that the main inclusions of non-metallic inclusions in GCr15 bearing steel are MgO-Al_2O_3-CaO composite inclusions and MnS, while a small amount of SiO_2- Al 2 O 3 and MgO-Al 2 O 3 composite inclusions. The size of the inclusions is mainly concentrated in the range of 3 ~ 8μm. A small amount of DS inclusions appear and the size range fluctuates greatly, up to 70μm. The morphology is round or nearly circular. VD has a strong ability to remove inclusions. After VD vacuum refining, the content of CaO in inclusions tends to increase. During the process of the sling to billet, the inclusions move to the area where the content of Al 2 O 3 increases. The inclusions in the final bearing steel slab The components are located in high Al 2 O 3 content (≥80%), a small amount of MgO (<20%) and low CaO (<5%). DS inclusions have strong randomness in their formation and removal.