摘要
为探究Si含量的变化对高碳铬轴承钢连铸坯截面不同位置晶界碳化物的影响,采用激光共聚焦显微镜模拟连铸坯截面相应位置的冷却速率(20.0、2.0、0.2℃/s),并以此冷却速率分别处理不同Si含量的高碳铬轴承钢。通过扫描电镜和X射线衍射仪检测并分析晶界碳化物析出量和尺寸分布。结果表明,Si质量分数的增加(0.29%~1.48%)导致C、Mo和Mn元素在晶界处的偏析程度降低,进而抑制了晶界碳化物的析出。同时,Si会增加晶界碳化物M_(23)C_(6)的吉布斯自由能,导致碳化物的析出延后,缩短了晶界碳化物的生长时间,由此可知,Si含量增加也存在细化晶界碳化物的效果。另外,在较低的冷却速率(0.2~2.0℃/s)下,Si含量对晶界碳化物的析出和尺寸变化影响显著。因此,可以推断出高碳铬轴承钢连铸坯芯部和糊状区(冷却速率较低)晶界碳化物的生长受Si含量的影响更加明显,适当提高Si质量分数(不大于0.71%)有助于晶界碳化物析出量的降低和尺寸的减小。本研究可为高品质轴承钢碳化物的精细调控进一步提供助力。
To investigate the effect of Si content on grain boundary carbides at different positions on the cross-section of high carbon chromium bearing steel continuous casting slab,laser confocal microscope was used to simulate the cooling rates(20.0,2.0,0.2℃/s)at corresponding positions on the cross-section of continuous casting slab,and high carbon chromium bearing steel with different Si content was treated at this cooling rate.The precipitation amount and size distribution of grain boundary carbide were detected and analyzed through scanning electron microscopy and X-ray diffraction.The results show that the increase of Si mass fraction(0.29%-1.48%)leads to the decrease of segregation degree for C,Mo and Mn elements at grain boundaries,and then inhibits the precipitation of carbide at grain boundaries.At the same time,Si increases the Gibbs free energy of grain boundary carbide M_(23)C_(6),resulting in the delay of precipitation time for carbide and shortening the growth time of grain boundary carbide.Thus,increasing Si content also has effect of refining grain boundary carbides.In addition,at a lower cooling rate(0.2-2.0℃/s),the Si content has a significant impact on the precipitation amount and size of grain boundary carbides.Therefore,it can be inferred that the influence of Si content on grain boundary carbides in high carbon chromium bearing steel continuous casting slab is mainly manifested in the core and mushy region with a low cooling rate.An appropriate increase in Si mass fraction(≤0.71%)helps to reduce the precipitation amount and size of grain boundary carbides.The study can further contribute to the fine regulation of carbides in high-quality bearing steels.
作者
徐太旭
何志军
杨鑫
韩啸
吕楠
XU Taixu;HE Zhijun;YANG Xin;HAN Xiao;LÜNan(School of Materials and Metallurgy,University of Science and Technology Liaoning,Anshan 114051,Liaoning,China;Key Laboratory of Green Low-Carbon and Intelligent Metallurgy Liaoning Province,Anshan 114051,Liaoning,China)
出处
《中国冶金》
CAS
CSCD
北大核心
2024年第2期52-60,共9页
China Metallurgy
基金
国家自然科学基金资助项目(52374339,52104331,51874171)
辽宁省兴辽英才计划特聘教授项目(XLYC2002064)。
关键词
高碳铬轴承钢
晶界碳化物
SI含量
冷却速率
微观偏析
high carbon chromium bearing steel
grain boundary carbides
Si content
cooling rate
microscopic segregation
