An Xueliang, Cao Wenquan, Zhang Xiaodan, Yu Jinku
State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China.
Central Iron and Steel Research Institute (CISRI), Beijing 100081, China.
Materials (Basel). 2024 Jun 17;17(12):2962. doi: 10.3390/ma17122962.
The effect of Nb alloying on the suppression of austenite grain coarsening behavior during pseudo-carburizing is investigated in high-temperature-carburized SAE4320 bearing steel. To explore the role of the Nb element in the pseudo-carburizing process, the morphology, composition, size, and distribution of NbC precipitates were analyzed. The results show that the fine austenite grain observed in Nb micro-alloyed steel is caused by the pinning effect of NbC precipitates, which hinders the coarsening of austenite grains and changes the growth dynamics of austenite grains. After the SAE4320 carburized bearing steel with the addition of 0.45 wt.% Nb element is kept at 1150 °C for 4 h, the PAG size is still below 20 μm, which indicates the Nb element has obvious advantages in limiting PAG growth at high temperatures and shows great potential for the development of high-temperature carburized bearing steel.
在高温渗碳的SAE4320轴承钢中，研究了铌合金化对伪渗碳过程中奥氏体晶粒粗化行为抑制的影响。为探究铌元素在伪渗碳过程中的作用，分析了NbC析出相的形貌、成分、尺寸和分布。结果表明，铌微合金钢中观察到的细小奥氏体晶粒是由NbC析出相的钉扎效应引起的，它阻碍了奥氏体晶粒的粗化并改变了奥氏体晶粒的生长动力学。添加0.45 wt.%铌元素的SAE4320渗碳轴承钢在1150℃保温4 h后，PAG尺寸仍低于20μm，这表明铌元素在限制高温下PAG生长方面具有明显优势，在高温渗碳轴承钢的开发中显示出巨大潜力。
