内燃机车柴油机横臂断裂失效分析  

Failure analysis of the diesel engine crossarm fracture on a diesel locomotive

作　　者：王华 吕永胜 郭航超 李硕 WANG Hua;LYU Yongsheng;GUO Hangchao;LI Shuo(CRRC Lanzhou Co.,Ltd.,Lanzhou,Gansu 730050,China)

机构地区：[1]中车兰州机车有限公司,甘肃兰州730050

出　　处：《轨道交通材料》2024年第3期67-70,共4页MATERIALS FOR RAIL TRANSPORTATION SYSTEM

摘　　要：针对某内燃机车柴油机配气机构横臂发生断裂失效,对失效的横臂进行了宏观及断口的观察分析、化学成分分析、金相显微组织分析和扫描电镜微观观察分析,结果表明:该横臂在制造过程中形成的工艺孔在焊接时由于焊接工艺不良,造成焊接组织粗大,Mo元素含量低,造成热疲劳性能下降,当柴油机气门闭合不良时,在气门排出的高温气体的反复作用下萌生了热疲劳裂纹,最终导致横臂断裂。In response to the fracture failure of the crossarm on a diesel engine valve mechanism,the failed crossarm is observed and analyzed by means of macroscopic and fracture analysis,chemical composition analysis,metallographic microstructure test and scanning electron microscope inspection.The results show that,due to the poor welding procedure and low Mo content,the fabrication holes formed in the manufacturing process of the crossarm give rise to a coarse welding structure and therefore decreased thermal fatigue performance.When the diesel valve is not closed properly,thermal fatigue cracks are generated on the crossarm under the repeated action of high temperature gas discharged from the valve,consequently leading to the crossarm fracture.

关 键 词：横臂断裂 热疲劳 热机械疲劳 腐蚀疲劳 失效分析 

分 类 号：U262.11[机械工程—车辆工程]