汽轮机转子10%Cr钢的高温低周疲劳特性  

High Temperature Low Cycle Fatigue Characteristics of Steam Turbine Rotor Steel 10%Cr

作　　者：崔璐[1] 康文泉 邹方 魏文澜 李臻[1] 王澎 CUI Lu;KANG Wenquan;ZOU Fang;WEI Wenlan;LI Zhen;WANG Peng(School of Mechanical Engineering,Xi'an Shiyou University,Xi'an 710065,China;HYCET Engine System(Jiangsu)Co.Ltd.,Yangzhong 212214,China)

机构地区：[1]西安石油大学机械工程学院,西安710065 [2]蜂巢动力系统(江苏)有限公司,扬中212214

出　　处：《材料研究学报》2021年第5期371-380,共10页Chinese Journal of Materials Research

基　　金：国家自然科学基金(51305348);西安石油大学青年创新团队基金(2019QNKYCXTD10);西安石油大学研究生创新与实践能力培养计划(YCS19113058)。

摘　　要：在分别控制应变和温度的条件下进行超超临界汽轮机转子10%Cr钢的高温低周疲劳实验,用SEM和TEM分析了10%Cr钢实验前后的表面形貌和亚晶粒结构。根据实验数据拟合应力-应变曲线、应力-寿命曲线和应变-寿命曲线,得到了反映材料高温低周疲劳特性的Ramberg-Osgood参数和Manson-Coffin参数。对比分析了低周疲劳实验初始和结束两个阶段的滞回曲线和应力-寿命曲线,并讨论了不同温度和不同应变幅控制的塑性应变。结果表明,在高温工况下10%Cr钢的塑性应变较为明显,随着应变幅的增大钢的疲劳寿命降低,随着循环周期的变化塑性应变速率经历了下降-过渡-上升三个阶段,曲线出现拐点。最大裂纹长度随循环周期呈非线性扩展,高温低周疲劳载荷使钢中的亚晶粒尺寸增大。High temperature low cycle fatigue performance of the ultra-supercritical steam turbine rotor steel 10%Cr was studied by controlling the strain and temperature, as well as the characterization of surface morphology and sub-grain structure with SEM and TEM for the steel before and after test. Based on the experimental data the Ramberg-Osgood parameters and Manson-Coffin parameters of the high temperature and low cycle fatigue characteristics of the material were obtained through fitting the stressstrain curves, stress-life curves and strain-life curves. The hysteresis loops and stress-life curves in the initial and final phases of the high temperature low cycle fatigue experiment were analyzed comparatively in terms of the relation between plastic strains with temperature and strain amplitude. Results show that the plastic strain of steel 10%Cr is much obvious under high temperature conditions, and the fatigue life of the material decreases with the increasing strain amplitude. The plastic strain rate experienced three stages with the fatigue cycle, namely the falling stage-the transition stage-the rising stage, and the plastic strain rate has an inflection point with the variation of fatigue cycles. The maximum crack length varied nonlinearly with the number of cycles, and as a result of the high temperature and low cycle fatigue process, the size of sub-grains of the steel increases.

关 键 词：金属材料 高温低周疲劳 应变与温度控制 塑性应变 裂纹扩展 循环软化 

分 类 号：TK265[动力工程及工程热物理—动力机械及工程]