某离心压缩机叶轮断裂失效原因分析
发布时间：2017.02.17
上虞风机针对某型号离心压缩机叶轮的断裂失效问题，采用金相检测手段检测了失效叶轮的焊接接头，并利用商用软件ANSYS从焊接的角度对叶轮结构受力进行了模拟计算与分析。结果发现，叶片和轮盘焊接角接头存在应力集中，进一步计算表明，在存在焊接缺陷的情况下，较小的作用力就能促使应力达到很大峰值，应力集中加速了裂纹的扩展及失稳，从而造成产品的结构失效。
关键词：离心压缩机；叶轮；断裂；应力集中
中图分类号：TH452 文献标志码：A
Fracture Failure Analysis of a Certain Centrifugal Compressor Impeller
Abstract: To analyze the fracture failure of a centrifugal compressor impeller, the metallography oberservation was adopted to characterize the defects in the welded joint, while the comerical software ANSYS was used to simulated and analyze the force of the compressor impeller. The result indicates the exist of stress concentration around the welded root between the blade and the wheel. The stress simulation results exhibit that even the relative low force could induce the pretty high stress valuewhen there is defect, which would result in crack and fracutre. As the result, the stress concentration could accelerate crack progagation and finally result in failure of the whole structure.
Key words: centrifugal compressor；impeller；failure；stress concentration
1 概述
随着离心压缩机叶轮制造工艺技术的发展，出现了焊接结构叶轮[1] ，这是风机叶轮制造工艺的一次变革，它使生产三元流、高速、高压、高强度、特殊性能、窄流道、高质量、长寿命及安全可靠的叶轮成为现实。近年来，高速离心叶轮已基本上全为焊接结构[2-4] 。
某型号焊接结构的离心叶轮采用低碳调质钢15MnNiCrMoV，运行一段时间后第3级叶轮发生失效，故障叶轮带有明显解体疲劳破坏特征。叶轮的宏观裂纹位置在叶片进口轮盖侧，具体如图1所示，可以清楚地观察到疲劳源位于叶片与轮盘焊接引弧区。
