在检查时某长时存放商用车发动机正时链条断裂的原因  

Reason for Fracture of Commercial Vehicle Engine Timing Chain during Inspection after Long Storage

作　　者：薛喜才 邵百明[1] 朱玲斌 XUE Xicai;SHAO Baiming;ZHU Lingbin(Passenger Vehicle Company,Shanghai Automotive Corporation Co.,Ltd.,Shanghai 201800,China)

机构地区：[1]上海汽车集团股份有限公司乘用车公司

出　　处：《机械工程材料》2019年第10期75-78,共4页Materials For Mechanical Engineering

摘　　要：某长时存放的商用车在销售前检查时其发动机突然熄火无法启动,经过排查发现正时链条断裂。通过断口形貌和显微组织观察、化学成分分析、硬度测试等方法研究了链条断裂的原因。结果表明:在整车放置过程中,在水汽腐蚀和张紧拉应力的共同作用下正时链条内链片销孔一侧先发生应力腐蚀断裂,然后在工作载荷的作用下销孔另一侧发生疲劳断裂。An commercial vehicle engine suddenly stalled and could not start over a pre-sale inspection after long storage.After investigation,it was found that a timing chain fractured.The reason for fracture of the timing chain was studied by fracture morphology and microstructure observation,chemical composition analysis,hardness testing,and so on.The results show that during the storage,the stress corrosion fracture occured at one side of internal chain piece pin hole of the timing chain by the combination of vapor corrosion and tension stress,and then the fatigue fracture occured at the other side of the pin hole by working loads.

关 键 词：正时链条 锈蚀 应力腐蚀 维护保养 

分 类 号：TH142.1[一般工业技术—材料科学与工程]