摘要
针对铁路机车铸造牵引座在长期服役过程中关键位置裂纹率偏高的问题,开展基于断口分析的铸造牵引座关键位置焊后疲劳失效机制研究。首先建立了经试验验证的牵引座有限元模型,确定了牵引座在标准牵引制动载荷下底座大圆弧处存在显著应力集中区域;然后,开展了基于标准载荷谱的牵引座高周疲劳试验,再现了宏观裂纹在应力集中区域的萌生和扩展过程;最后,对疲劳裂纹失效区域进行了断口分析、扫描电镜(SEM)观察、金相检验和能谱分析(EDS),表明裂纹区域存在明显的焊接修复痕迹及热处理组织。研究结果表明,牵引座疲劳开裂失效是底座圆弧处应力集中与焊接修复引入的缺陷共同作用的结果,应着重控制底座大圆弧处的铸造质量,避免补焊。该研究可为铁路货运的安全高效运营和零部件的维护检修提供理论指导。
Aiming at the problem of high crack rate in key positions of cast traction seats for railway locomotives during long-term service,a study was conducted on the post-weld fatigue failure mechanism at key positions of cast traction seats based on fracture analysis.Firstly,a experimentally validated finite element model of the traction seat was established,and it was determined that there is a significant stress concentration area at the large arc of the base of the traction seat under standard traction braking loads.Then,a high cycle fatigue test was conducted on the traction seat based on the standard load spectrum,reproducing the initiation and propagation process of macroscopic cracks in the stress concentration area.Finally,fracture analysis,scanning electron microscopy(SEM)observation,metallographic examination,and energy dispersive spectroscopy(EDS)were performed on the fatigue crack failure area,indicating the presence of obvious welding repair marks and heat-treated microstructure in the crack area.The research results indicate that the fatigue cracking failure of the traction seat is the result of the combined effect of stress concentration at the base arc and defects introduced by welding repair.It is important to focus on controlling the casting quality at the large arc of the base and avoid welding repairs.The research can provide theoretical guidance for the safe and efficient operation of railway freight and the maintenance and repair of parts.
作者
朱涛
齐红瑞
太万秋
张帆
王超
肖守讷
Zhu Tao;Qi Hongrui;Tai Wanqiu;Zhang Fan;Wang Chao;Xiao Shoune(State Key Laboratory of Rail Transit Vehicle System,Southwest Jiaotong University,Chengdu 610031,China;CRRC Datong Co.,Ltd.,Datong 037038,China)
出处
《华东交通大学学报》
2025年第4期29-36,共8页
Journal of East China Jiaotong University
基金
四川省自然科学基金创新研究群体项目(2025NSFTD0014)
国家重点研发计划(2022YFB4301201)。
关键词
机车铸造牵引座
高周疲劳试验
断口分析
疲劳失效
locomotive casting traction seat
high cycle fatigue test
fracture analysis
fatigue failure
