XE112-2000型风力发电机叶片连接用高强度螺栓在服役过程中频繁断裂，通过宏观观察、金相检验、力学性能测试及化学成分分析等方法对螺栓的断裂原因进行了分析。结果表明：螺栓断裂形式为腐蚀疲劳断裂，主要原因是螺栓的螺纹成形工艺为先调质后滚压成形，螺纹外侧表面受到挤压，导致螺纹顶部受到相反的拉应力作用，此外，又因为螺栓受到加工硬化的影响，产生较大的残余拉应力，增加了产生微裂纹和表面缺陷的可能，导致在螺纹顶部偏中心处产生了应力腐蚀裂纹。在之后的服役过程中，由于疲劳作用，裂纹处产生应力集中，导致裂纹快速扩展，最终螺纹发生腐蚀疲劳断裂。

The high strength bolts used for blade connection of XE112-2000 wind turbine fractured frequently in service. The causes of fracture on bolt were analyzed by means of macro observation, metallographic examination, mechanical property test and chemical composition analysis. The results show that the fracture mode of bolt was corrosion fatigue fracture. The main reason was that the thread forming process of the bolt was quenching and tempering first and then rolling forming. The outer surface of thread was squeezed, which led to the opposite tensile stress on the top of thread. In addition, due to the influence of work hardening, the bolt produced large residual stress, which increased the possibility of microcracks and surface defects, resulting in the stress corrosion cracks at the center of the top of thread. In the later service, due to fatigue action, stress concentration occured at the crack, which led to rapid crack growth, and finally corrosion fatigue fracture occurred in thread.