某风电场3 MW机组在投运后,多次发生叶片连接螺栓断裂事故。采用宏观观察、化学成分分析、力学性能测试、金相检验、资料对比核查、登机现场检查等方法,对螺栓的断裂原因进行研究。结果表明:螺栓因受到周期性交变应力作用而发生疲劳断裂;螺栓的装配精度不足,安装过程中存在偏心现象,导致螺栓杆部与螺栓孔内壁紧密接触,局部受挤压力过大;安装时,润滑膏涂抹控制不到位,造成叶片连接螺栓预紧力不均匀,最终导致螺栓发生疲劳断裂。建议更换损坏的叶片连接高强螺栓,严格遵守高强螺栓的装配要求,正确涂抹螺栓润滑膏,以确保机组安全稳定运行。

After the 3 MW wind turbine was put into operation, the blade connecting bolts were broken many times. The fracture causes of bolts were studied by means of macroscopic observation, chemical composition analysis, mechanical property test, metallographic examination, data comparison and verification, and boarding site inspection. The results show that the bolts suffered fatigue fracture due to periodic alternating stress. The assembly accuracy of bolts was insufficient, and there was eccentric phenomenon in the installation process, which led to the close contact between the bolt rod and the inner wall of the bolt hole, and the local extrusion force was too large. During installation, the application of lubricating paste was not controlled in place, resulting in uneven preload of blade connecting bolts, which eventually led to fatigue fracture of bolts. It was recommended to replace the damaged blade connecting high-strength bolts, strictly comply with the assembly requirements of high-strength bolts, and correctly apply bolt lubricating paste to ensure the safe and stable operation of the turbine.