论文部分内容阅读
30万千瓦汽轮机,为N300-165/550/550型中间再热冷凝式汽轮机,累积运行时间1124小时后,发生第十二压力级叶片断裂事故。鉴于十二压力级叶片事故比较复杂,一些断裂现象在以前的汽轮机叶片损坏中未发现过。由于断裂原因不清楚,于是只得把整级旧叶片卸下,然后按原设计要求装上新叶片,但运行1400小时又发生同类型的事故。为了找出十二压力级叶片损坏的原因,我们时第一次事故的十四片有裂纹的叶片,进行了解剖试验,试验项目有:叶片材料质量检查,小脚裂纹的宏观特征统计,叶片断口宏观与微观观察,叶片小脚裂纹源点与黑斑的特征分析。通过这一系列的试验与分析,发现叶片断裂的特征和叶片运行时受力特点的一些内在联系,认为十二压力级叶片小脚断裂的原因是接触振动氧化疲劳。
The 30MW turbine is N300-165 / 550/550 type intermediate reheat condensing steam turbine, and the twelfth pressure level blade rupture occurs after 1124 hours of accumulated operation time. Given the complexity of the twelve-pressure-level blade accident, some rupture phenomena were not found in previous turbine blade damage. As a result of the fracture is not clear, so had to remove the entire level of old leaves, and then according to the original design requirements of new leaves, but after 1400 hours of operation and the same type of accident occurred. In order to find out the cause of the damage of the 12-pressure blade, we dissected the fourteen cracked leaves in the first accident. The test items included leaf material quality inspection, macroscopic feature statistics of foot cracks, Macroscopical and microscopic observation, the characteristic analysis of the source point and black spot of the leaflet small crack. Through a series of experiments and analyzes, we find some inherent relationships between the characteristics of blade fracture and the characteristics of the blade during operation. It is concluded that the reason for the fracture of the tip of the twelve-pressure blade is the contact fatigue caused by vibration.