18CrNiMo7-6高铁齿轮钢的疲劳极限评定  

Fatigue Limit Assessment of 18CrNiMo7-6 High-Speed Train Gear Steel

作　　者：张军豪 王文先(导师)[1] 闫志峰[1] 段德盛 张红霞[1] 张锦文[2] 周峻 ZHANG Junhao;WANG Wenxian;YAN Zhifeng;DUAN Desheng;ZHANG Hongxia;ZHANG Jinwen;ZHOU Jun(College of Materials Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,China;Technology Center,Taiyuan Iron&Steel(Group)Co.,Taiyuan 030003,China)

机构地区：[1]太原理工大学材料科学与工程学院,太原030024 [2]山西太钢不锈钢股份有限公司技术中心,太原030003

出　　处：《机械工程材料》2023年第3期19-23,36,共6页Materials For Mechanical Engineering

基　　金：山西省重点研发计划项目(201903D111008);国家自然科学基金资助项目(51775366)。

摘　　要：在不同最大循环应力(600~880 MPa)和应力比0.1下对18CrNiMo7-6高铁齿轮钢进行棘轮试验和疲劳试验,先通过对稳定阶段的棘轮应变差值和温升与最大循环应力进行拟合来预测疲劳极限,然后再基于由棘轮应变差值和温升计算的断裂疲劳熵来预测疲劳极限,并将不同方法的预测结果与试验结果进行对比。结果表明:由稳定阶段的棘轮应变差值和温升与最大循环应力的线性拟合得到的疲劳极限分别为664.9,681.4 MPa,与由疲劳试验得到的疲劳极限(689.0 MPa)的相对误差分别为1.11%,3.50%,说明用这2种方法预测疲劳极限的精度较高;当最大循环应力为673.2 MPa时,断裂疲劳熵值由0.1 MJ·m^(-3)·K^(-1)以下突变增至0.46 MJ·m^(-3)·K^(-1),由此预测得到的疲劳极限为673.2 MPa,与疲劳试验结果的相对误差为2.3%,预测精度较高。The ratchet test and fatigue test were carried out on 18CrNiMo7-6 high-speed train gear steel at different maximum cyclic stresses(600-880 MPa)and stress ratio of 0.1.The fatigue limit was predicted by fitting the ratchet strain difference and temperature rise to the maximum cyclic stress at the stable stage,and then was predicted with the fracture fatigue entropy calculated from ratchet strain difference and temperature rise.The predicted results by different methods were compared with test results.The results show that according to the linear fitting results between the ratchet strain difference and the temperature rise and the maximum cyclic stress,the fatigue limits were 664.9,681.4 MPa,respectively,and the relative errors of predicted fatigue limit with those obtained by fatigue tests were 3.50%and 1.11%,respectively,indicating that these two methods could predict the fatigue limit with high accuracy.When the maximum cyclic stress was 673.2 MPa,the fracture fatigue entropy changed from less than 0.1 MJ·m^(-3)·K^(-1) to 0.46 MJ·m^(-3)·K^(-1) suddenly.The fatigue limit predicted by this method was 673.2 MPa,and the relative error of the predicted fatigue limit with the fatigue test result was 2.3%,indicating high prediction accuracy.

关 键 词：18CrNiMo7-6钢 棘轮应变 温升 断裂疲劳熵 疲劳极限评定 

分 类 号：TG115.5[金属学及工艺—物理冶金]