40Cr钢的冲击疲劳性能及疲劳断口分析  

Study on Impact Fatigue Properties and Fracture Surface of 40Cr Steel

作　　者：江强[1] 周细应[1] 施蓓倩[1] 袁超[1] 徐燕菁[1] 

机构地区：[1]上海工程技术大学材料工程学院,上海201620

出　　处：《热加工工艺》2012年第22期63-65,共3页Hot Working Technology

基　　金：上海市教委科技发展基金项目(11CXY57);上海市教委大学生创新实践计划项目(CX1005006);上海工程技术大学科研创新项目(2011yjs18)

摘　　要：采用超声疲劳试验法研究40Cr钢在105～1010周次,受到冲击前后的疲劳性能,用扫描电镜分析疲劳断口形貌特征。结果表明,40Cr钢的S-N曲线始终保持下降趋势,随着疲劳循环数的增加,循环应力的变化幅度减小;受冲击后,在105～1010周次循环范围内,40Cr钢的疲劳寿命下降的趋势明显加快。在280MPa的应力下,40Cr钢未受冲击时的疲劳寿命为28.359×106周次,而受冲击后的疲劳寿命骤降到18.653×106周次,两者存在明显差距。40Cr钢受冲击前后的断口形貌无明显差异,受冲击后试样的疲劳裂纹在两侧的扩展速度更快,瞬断区面积偏大较为明显,从扩展区断口显微形貌观察到明显的疲劳辉纹。The fatigue behavior before and after the impact of 40Cr steel between 105 -1010 cycles was studied by ultrasonic fatigue testing technique. The fracture surface of the specimens was investigated by SEM. The results show that the S-N curve of 40Cr steel decreases, with the increase of the number of cycles, the range-ability of cyclic stress decreases. After the impact, the downward trend of the fatigue life goes faster obviously between 105-1010 cycles. The fatigue cycles a 280 MPa cyclic stress is found to be 28.359 × 106 times, but plunged to 18.653 × 106 times after the impact, a significan difference between them. The observation of fracture surface shows that there is no obvious difference in the samples＇ fracture morphology between the samples before and after the impact, and the fracture-speed of the fatigue crack in the samples with impact goes faster at both sides. The transient breaking area of the impact samples is obvious bigger. In addition, the fatigu, striation area was found in the fracture surface of specimen.

关 键 词：40CR钢 冲击疲劳 疲劳寿命 断口形貌 

分 类 号：TG113.2[金属学及工艺—物理冶金]