超超临界汽轮机转子TMF 损伤机理以及与本构模型的耦合

项目名称： 超超临界汽轮机转子TMF 损伤机理以及与本构模型的耦合

项目编号： No.51305348

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 机械、仪表工业

项目作者： 崔璐

作者单位： 西安石油大学

项目金额： 26万元

中文摘要： 火力发电机组启动关闭过程中，由于热应力引起的汽轮机转子热疲劳（TMF）加速转子失效。本课题选用现代超超临界(USC)汽轮机9-12%Cr转子钢为研究对象，通过同一疲劳蠕变载荷在多试件上的试验，结合透镜（TEM）等分析手段，探求析出相(M23C6,MX)以及组织结构（亚晶粒大小和位错密度）随载荷时间的演变关系，同时探求TMF损伤机理。通过对比试验揭示影响组织结构变化的力学因素（应变振幅，应变率）和温度因素（恒定温度，变化温度），寻求平均亚晶粒大小与粘塑性形变之间随载荷时间之间的关系。在此基础上，耦合亚晶粒的变化规律优化粘塑性材料本构模型，优化对TMF载荷下的力学性能以及疲劳损伤分析。课题旨在为超超临界汽轮机的设计优化，运行工况优化，以及安全监控等方面提供理论基础。

中文关键词： 9-12%Cr钢；热交变载荷；损伤；微观组织；本构模型

英文摘要： In terms of start-up and shut-down process of coal-fired power plants, thermo- mechanical fatigue (TMF) accelerates the steam turbine rotor failure. In this project, a modern 9-12%Cr steel, which is used in steam turbines of ultra-supercritical (USC) power plants, is investigated. By means of cross-section transmission electron microscopy (TEM), the evolution of precipitates (M23C6, MX) and microstructure (subgrain size and dislocation density) as well as the mechanism of TMF damage is determined by multi-specimen TMF experiments under identical creep fatigue loadings. Using comparison experiments, the influences of mechanical (strain amplitude and strain rate) and thermal (isothermal and anisothermal) factors are investigated. the relationship between average subgrain size and viscoplastic deformation are analyzed. On this basis, the subrgain evolution and damage mechanism will be coupled to an existing viscoplastic material model, and furthermore the description of deformation behavior and life assessment under TMF loadings will be optimized. The project is aimed at providing a theoretical basis for design optimization, operating conditions optimization and security monitoring of USC steam turbines

英文关键词： 9-12%Cr steel；thermomechanical fatigue (TMF)；damage；microstructure；constitutive material model