【摘要】 对 40 Cr钢经淬火和高温回火的试样在恒应变ε=± 0 . 5 %下进行了疲劳寿命测定 ,并与相同加载条件下 ,不同疲劳损伤程度而经过中间退火修复后的疲劳寿命进行了对比 ,发现经过中间退火修复后 ,极限强度下降不超过 7% ,但疲劳总寿命是原来未经退火修复的二倍。修复效果和延寿效果与循环应变量和循环周次有关更多还原

【Abstract】 The low cycle fatigue tests with ε =±0.5% were carried out for specimens of steel 40Cr quenched and tempered at high temperature. In condition of the same fatigue loading, some specimens were annealed after defined fraction of life time and then resumed fatigue test .By comparison,it was found that after this kind of recovery annealing the decrease of ultimate tensile strength is less than 7%, but the accumulative total cycles is twifold than that of unannealed specimens.The effectiveness of repairing and life prolonging is closely related to strain amplitude and cycling number. By TEM observation, it is obvious that after intermidiate annealing the variation of microstructure took place, and did not return to original microstructure. It should be emphasized that the role of variation in geometry and distribution of precipitated carbides after low cycle fatigue damage and intermediate annealing is important for reducing fatigue crack nucleation and prolonging life.更多还原