风力发电机组机舱立支撑结构法兰连接螺栓断裂原因分析

Fracture Analysis of Flange Bolt Used for Structural Support of Wind-Power Generator Cabin

某风电场810 kW风力发电机组机舱立支撑结构法兰连接螺栓发生断裂,通过搭建模型分别对风机机舱立支撑结构在3种不同工况下进行了受力分析,并通过宏观检测、显微组织分析、断口形貌分析等方法对其断裂原因进行分析。结果表明,法兰连接螺栓断裂属于疲劳失效,螺纹处存在超标脱碳层是导致其疲劳断裂的主要原因。对此提出采用同一厂家、同一强度等级的螺栓,同时将该法兰连接螺栓更换为强度等级更高的12.9级连接螺栓等建议,以防类似断裂事故再次发生。

The fractured flange bolt used for structural support of wind-powered generator cabin was investigated by means of macro-morphology inspection,microstructure analysis,fracture morphology analysis and numerical simulation.The investigation showed the failure of flange bolt was fatigue fracture.The thicker decarburized layer in the thread was the main cause of the fracture of the bolt.Put forward the suggestions to adopt the bolts manufactored in the same factories and with the same grade,and exchange the original flange bolt into the ones with the level of 12.9 to prevent the similar fault happening once more.