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通过对300MW机组高压、中压缸螺栓断裂的常规试验分析及断口扫描电镜分析和能谱分析,指出1号机汽缸螺栓断裂的主要原因系疲劳所致,而断裂螺杆上的光谱灼伤促进了疲劳的产生. 相似文献
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对某电厂升压站500 kV线路螺栓断裂事故进行分析,认为该螺栓因用材不当和表面加工质量不符合要求,且长期在腐蚀性环境中使用并承受交变弯曲应力作用,导致其发生腐蚀性疲劳断裂. 相似文献
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对沈阳电厂3号机自动主汽门断裂螺栓,从宏观、光谱、组织、性能、热处理方面进行观察、试验分析,认为该螺栓的材质不是20Cr1Mo1VTiB而是25Cr2Mo1V;螺栓断裂系材料脆化失效所致;脆化失效的螺栓通过热处理的方法可以恢复其冲击韧性等性能。 相似文献
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通过结构分析、化学成分分析、硬度检测、宏观断口形貌观察和金相组织观察等方法,对某电厂汽轮机中压内缸定位双头螺栓断裂原因进行了分析。结果表明:螺栓断裂的性质属于脆性沿晶断裂,主要原因为螺栓的组织发生异常,内部产生微观裂纹,局部承载过大。 相似文献
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N100-95/535汽轮机运行六万多小时后,机组大修。汽轮机盖缸后,进行法兰加热送汽,当温度达150℃、压力为0.392MPa时,发现高压缸的M120螺栓断裂,断口全貌如图1. 相似文献
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《Dielectrics and Electrical Insulation, IEEE Transactions on》2004,11(6):1037-1048
Existing brittle fracture models have been reviewed and their applicability to explain the in-service brittle fracture failure of composite (nonceramic) insulators is evaluated. It is shown that the only brittle fracture model that can explain all aspects of the brittle fracture process is a model based on the formation of nitric acid solutions in-service. The chemical cause of brittle fracture is identified in this work and recommendations are made on how to avoid brittle fracture in-service by proper selection of composite insulator rods resistant to brittle fracture. An attempt is made to clarify misconceptions that exist in the literature regarding the causes of brittle fracture and the most suitable prevention methods. 相似文献
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某电厂发生锅炉磨煤机变速箱高速轴断裂,双列调心滚子轴承损坏.通过振动信号频谱分析和轴的宏观、微观及化学成分综合分析,认为高速轴斜齿轮在较大的冲击负荷工况下产生的轴向力,使轴承游隙变化,导致轴承损坏.随着变速箱振动速度和加速度的加大,高速轴在表面应力集中处产生裂纹并最终导致断裂损坏.基于此,提出改进意见以及类似故障的防范措施. 相似文献
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In this paper, we present a novel non-uniform shaped cantilever based DC contact radio frequency microelectromechanical systems (RF MEMS) switch. This switch can be employed for various wireless mobile applications in frequency range of DC-10 GHz as it shows excellent RF characteristics with low actuation voltage. The design is optimized in the terms of electrostatic actuation mechanism, which included switch beam thickness, beam gap, spring shape and materials. Also, it’s optimized shape and size of contact geometry and material ensures the high reliability, high isolation and very low insertion loss. The main features of this switch are simplicity of structure, reliability of contact, excellent RF characteristics, low actuation voltage and excellent figure of merit. We investigate the proposed design with Coventorware software for electromechanical and electromagnetic analysis and, get very promising results. The paper briefly outlines the design of RF MEMS switch and also focuses on the analysis of various switching parameters. 相似文献
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台区线损管理是县级供电企业线损管理的重点和难点,低压线路特有的技术状况和用户用电的多样性决定了低压线损成因的错综复杂。针对线损管理实践中常见的几种台区线损率异常现象,着重分析其形成原因,并提出相应的解决方法。 相似文献