Wu Qihua, Tan Bingzhi, Pang Jianchao, Shi Feng, Jiang Ailong, Zou Chenglu, Zhang Yunji, Li Shouxin, Zhang Yanyan, Li Xiaowu, Zhang Zhefeng
State Key Laboratory of Engine and Powertrain System, Weichai Power Co., Ltd., 197A Fushou East Street, Weifang 261061, China.
Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China.
Materials (Basel). 2024 Aug 28;17(17):4266. doi: 10.3390/ma17174266.
Tensile and low-cycle fatigue tests of high-strength compacted graphite cast iron (CGI, RuT450) were carried out at 25 °C, 400 °C, and 500 °C, respectively. The results show that with the increase in temperature, the tensile strength decreases slowly and then decreases rapidly. The fatigue life decreases, and the life reduction increases at high temperature and high strain amplitude. The oxide layer appears around the graphite and cracks at high temperature, and the dependence of crack propagation on ferrite gradually decreases. With the increase in strain amplitude, the initial cyclic stress of compacted graphite cast iron increases at three temperatures, and the cyclic hardening phenomenon is obvious. The fatigue life prediction method based on the energy method and damage mechanism for compacted graphite cast iron is summarized and proposed after comparing and analyzing a large amount of fatigue data.
分别在25℃、400℃和500℃下对高强度蠕墨铸铁（CGI，RuT450）进行了拉伸和低周疲劳试验。结果表明，随着温度的升高，抗拉强度先缓慢下降，然后迅速下降。疲劳寿命降低，且在高温和高应变幅下寿命降低幅度增大。石墨周围在高温下出现氧化层并产生裂纹，裂纹扩展对铁素体的依赖性逐渐降低。随着应变幅的增加，蠕墨铸铁在三个温度下的初始循环应力均增大，循环硬化现象明显。在对比分析大量疲劳数据后，总结并提出了基于能量法和损伤机制的蠕墨铸铁疲劳寿命预测方法。
