机车牵引杆断裂的原因分析  

Fracture Cause Analysis of Locomotive Traction Rod

作　　者：杨其全 YANG Qiquan(Metals and Chemistry Research Institute,China Academy of Railway Sciences Corporation Limited,Beijing 100081,China)

机构地区：[1]中国铁道科学研究院集团有限公司金属及化学研究所,北京100081

出　　处：《铁道机车车辆》2023年第4期144-149,共6页Railway Locomotive & Car

摘　　要：为分析机车牵引杆断裂原因,对发生断裂的机车牵引杆进行宏微观形貌、金相、化学成分、拉伸等检验,结果表明,2处疲劳断口之间存在占断口总面积1/4~1/3的未熔合断口,断口面上出现的大面积未熔合是导致断裂的主要原因,焊缝根部存在较多气孔缺陷以及焊缝余高不足,加速了裂纹的疲劳扩展。X射线探伤对未熔合缺陷不敏感,使得不合格产品出厂,为牵引杆断裂埋下了隐患。增加超声波探伤可避免存在类似焊接缺陷的部件投入使用。To analyze the fracture cause,macro and micro appearance,metallography,chemical composition and tensile test were carried out on the fractured locomotive traction rod.The results show that there is incomplete fusion between the two fatigue fracture surfaces,which accounts for 1/4~1/3 of the total fracture area.A large area of non fusion on the fracture surface is the main reason for the fracture.There are many blowholes at the root of the weld and insufficient weld reinforcement,which accelerate the fatigue crack propagation.X-ray detection is not sensitive to the incomplete fusion defects,which makes the unqualified products leave the factory and lays a hidden danger for the traction rod fracture.By adding ultrasonic testing,the parts with similar welding defects can be avoided to be put into use.

关 键 词：牵引杆 断裂 未熔合 X射线探伤 

分 类 号：U269.6[机械工程—车辆工程]