An investigation into failure analysis of interfering part of a steam turbine journal bearing

Case studies in engineering failure analysis Pub Date : 2014-10-01 DOI:10.1016/j.csefa.2014.04.001

M. Mehdizadeh , F. Khodabakhshi

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引用次数: 12

Abstract

Journal bearings as so sensitive parts of steam turbines are very susceptible to failure through different mechanisms of wear, fatigue and crush during service conditions. Failure occurring through these mechanisms lead to turbine completely shut down as a result of interfering in working conditions of bearing different parts. In this research, failed interfered part of a journal bearing related to a 320,000 kW steam turbine was examined. Failure analysis investigations were performed by utilizing of stereographic, optical microscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) analysis and hardness test. Surface crush, large amounts of surface cracks, no noticeable changes of failed surface chemical composition and microstructure with significant hardness improvement were the main obtained results. The studies were revealed that the bearing part loosing and inappropriate clearance can produce relative displacements under cyclic gradient loading. This condition was detrimental for the service life of turbine journal bearing via failure through fretting fatigue mechanism.

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汽轮机轴颈轴承干扰部分失效分析研究

轴颈轴承作为汽轮机的敏感部件，在使用过程中极易因磨损、疲劳和挤压等不同机制而发生失效。由于轴承各部件的工作状态受到干扰，这些机构发生的故障导致汽轮机完全停运。在本研究中，对320,000 kW汽轮机轴颈轴承的失效干扰部分进行了检测。采用立体成像、光学显微镜、扫描电镜(SEM)、能谱分析(EDS)和硬度测试等方法进行了失效分析。获得的主要结果是表面破碎，表面裂纹大量，失效表面化学成分无明显变化，显微组织硬度明显提高。研究表明，在循环梯度荷载作用下，轴承部件松动和间隙不适当会产生相对位移。这种情况不利于涡轮轴颈轴承的微动疲劳失效。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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Case studies in engineering failure analysis

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