某四缸柴油机主轴承盖螺栓断裂失效

Failure Analysis of the Main Bearing Cap Bolt in a Four Cylinder Diesel Engine

针对一起台架试验中的柴油机主轴承盖螺栓断裂问题,对断口进行了宏观分析、微观分析、金相组织检验等,对螺栓的断裂原因进行了分析。结果表明:该螺栓失效是典型的疲劳失效,主要原因是螺栓螺纹牙底存在原始裂纹,产生疲劳断裂,通过提高螺栓搓丝质量避免类似问题的发生。

In view of bench testg in diesel engine main bearing cap bolt break question, has carried on the macroscopic analysis, the microscopic analysis, the Microstructure examination together to the fracture and so on, has carried on the analysis to bolt＇s break reason. The result indicated： This bolt ex- piration is the typical fatigue failure, the primary cause is the bolt root of thread existence primitive crack, has the endurance failure, through improves the bolt twisted thread quality to avoid the similar question the occurrence.