列车支撑转辙机弯板开裂失效分析  

Cracking failure analysis of bending plate of train support switch machine

作　　者：戴开明 DAI Kaiming(China North Industries Group Jiangshan Heavy Industry Research Institute Co.,Ltd.,Xiangyang 441057,Hubei China)

机构地区：[1]中国兵器工业集团江山重工研究院有限公司,湖北襄阳441057

出　　处：《中国铸造装备与技术》2022年第3期35-40,共6页China Foundry Machinery & Technology

摘　　要：某铁路段列车支撑转辙机弯板在服役过程中发生断裂。对断裂弯板进行了生产厂家工艺调研、宏观检验、化学成分分析、金相检验和断口分析。结果表明:列车支撑转辙机弯板断裂失效为疲劳断裂。开裂转辙机弯板采用双筋板焊接结构,开裂基本沿短竖焊缝熔合线分布。该焊缝在正常工况下,主要受转辙机的承重压力及车辆通过时弯板上下振动形成的交变载荷,属于受工作应力最大的区域。弯板开裂的主要原因为受正应力的短竖焊缝焊接接头质量较差,存在较多焊接缺陷,缺陷部位在铁路上承受较大的交变载荷作用,焊接裂纹扩展或者萌生疲劳裂纹,进而裂纹扩展,发生开裂。The bending plate of the train support switch machine in some railway section breaks during the service process.The manufacturer's process investigation,macro inspection,chemical composition analysis,metallographic inspection and fracture analysis have been carried out on the fractured bending plate.The results show that the fracture failure of the bending plate of the train support switch machine is fatigue fracture.The bending plate of the crack switch machine adopts a double-ribbed plate welding structure,and the cracks are basically distributed along the fusion line of the short vertical weld.Under normal working conditions,the welding seam is mainly affected by the load-bearing pressure of the switch machine and the alternating load formed by the up and down vibration of the bending plate when the vehicle passes,which belongs to the area with the largest working stress.The main reason for the cracking of the bending plate is that the quality of the short vertical weld joint under normal stress is poor with many welding defects.The defect part is subjected to a large alternating load on the railway,and the welding crack expands or a fatigue crack is initiated,and then the crack expands and cracks occur.

关 键 词：Q235钢 支撑转辙机 弯板 疲劳裂纹 应力集中 失效分析 

分 类 号：TG247[金属学及工艺—铸造]