叶轮用FV520B-Ⅰ钢超高周疲劳行为  

Super-high-cycle fatigue behavior of FV520B-Ⅰ steel used in impellers

作　　者：孙清超[1] 孙克鹏 石博文[1] 张元良[1] SUN Qingchao;SUN Kepeng;SHI Bowen;ZHANG Yuanliang(School of Mechanical Engineering,Dalian University of Technology,Dalian 116024,China)

机构地区：[1]大连理工大学机械工程学院

出　　处：《哈尔滨工程大学学报》2019年第12期2057-2062,共6页Journal of Harbin Engineering University

基　　金：国家自然科学基金项目(51875081)

摘　　要：为了能够定量地预测离心压缩机叶轮材料FV520B-Ⅰ超高周疲劳寿命,本文在岛津USF-2000超声疲劳试验机上进行疲劳试验。试样断裂后利用扫描电镜对试样断口形貌进行观察,测得裂纹源区特征区域-夹杂物、GBF(granular bright facet)和鱼眼区的尺寸,利用Murakami提出的应力强度因子公式计算出特征区域边界处的应力强度因子幅值ΔK,分析特征区域对超高周疲劳寿命的重要影响;比较适用于超高周疲劳寿命计算的裂纹萌生模型和利用Paris方程拟合的寿命模型,结果显示后者与实验数据一致性更好,预测寿命与实验寿命均在一个数量级内,平均误差约为26. 9%。研究内容对FV520B-I钢夹杂物控制及离心压缩机叶轮寿命预测具有积极意义。To quantitatively predict the super-high-cycle fatigue life of FV520 B-Ⅰ steel used in the manufacture of centrifugal-compressor impellers,we conducted fatigue tests on a Shimadzu USF-2000 ultrasonic fatigue testing machine. After the specimens had been broken,we used a scanning electron microscope( SEM) to carefully observe their fracture morphologies. From the SEM images,we also measured the sizes of the inclusions in characteristic areas,the granular bright facets( GBFs),and the fish-eye area at the origin of the crack. We calculated the stress intensity factors( SIFs) ΔK at the periphery of the inclusions,GBFs,and fish-eye areas using the SIF equation proposed by Murakami,and consider the influence of characteristic areas on very-high-cycle fatigue life. We compare and contrast the results of the crack initiation model as well as the life model fitted by the Paris equation.The results show that the latter agrees well with the experimental data. The predicted and experimental lives are within an order of magnitude,with an average error of about 26. 9%. This research has significance regarding the control of inclusions of FV520B-Ⅰ steel and the prediction of the fatigue life of the centrifugal-compressor impeller.

关 键 词：超高周疲劳 FV520B钢 夹杂物 疲劳寿命 断口形貌 GBF区 应力强度因子 Paris方程 

分 类 号：TH114[机械工程—机械设计及理论] TH122