Effects of rare earth elements on inclusions and impact toughness of high-carbon chromium bearing steel
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2019年第7期
论文作者：Chaoyun Yang Yikun Luan Dianzhong Li Yiyi Li
文章页码：1298 - 1308
摘 要：High-carbon chromium bearing steels with different rare earth（RE） contents were prepared to investigate the effects of RE on inclusions and impact toughness by different techniques. The results showed that RE addition could modify irregular Al2O3 and MnS into regular RE inclusions. With the increase of RE content, the reaction sequence of RE and potential inclusion forming elements should be O, S, As, P and C successively. RE inclusions containing C might precipitate in molten steel and solid state, but the precipitation temperature was significantly higher than that of carbides in high-carbon chromium bearing steel. For experimental bearing steels, the volume fraction of inclusions increased steadily with the increase of RE content, but smaller and more dispersed inclusions could be obtained by 0.018% RE content compared with bearing steel without RE, whereas the continuous increase of RE content led to an increasing trend for inclusion size and a gradual deterioration for inclusion distribution. RE addition could improve the transverse impact toughness and isotropy of bearing steel, and for modified highcarbon chromium bearing steel by RE alloying, the increase of RE content continuously increased both transverse and longitudinal impact toughness until excessive RE addition.
Chaoyun Yang，Yikun Luan，Dianzhong Li，Yiyi Li
Institute of Metal Research, Chinese Academy of SciencesSchool of Materials Science and Engineering, University of Science and Technology of China
摘 要：High-carbon chromium bearing steels with different rare earth（RE） contents were prepared to investigate the effects of RE on inclusions and impact toughness by different techniques. The results showed that RE addition could modify irregular Al2O3 and MnS into regular RE inclusions. With the increase of RE content, the reaction sequence of RE and potential inclusion forming elements should be O, S, As, P and C successively. RE inclusions containing C might precipitate in molten steel and solid state, but the precipitation temperature was significantly higher than that of carbides in high-carbon chromium bearing steel. For experimental bearing steels, the volume fraction of inclusions increased steadily with the increase of RE content, but smaller and more dispersed inclusions could be obtained by 0.018% RE content compared with bearing steel without RE, whereas the continuous increase of RE content led to an increasing trend for inclusion size and a gradual deterioration for inclusion distribution. RE addition could improve the transverse impact toughness and isotropy of bearing steel, and for modified highcarbon chromium bearing steel by RE alloying, the increase of RE content continuously increased both transverse and longitudinal impact toughness until excessive RE addition.
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