摘要
超声疲劳是一种加速的疲劳试验方法,它的测试频率(20kHz)远远超过了常规疲劳测试频率(小于200 Hz).超声疲劳试验研究表明50#车轴钢和40Cr钢直到1010个应力循环后仍会发生疲劳断裂,并不存在常规疲劳试验曲线所示的“疲劳极限’,因此用107周次的疲劳试验数据进行疲劳强度设计并不安全. 50#车轴钢和40Cr钢超声疲劳性能优于常规疲劳性能.扫描电镜分析表明,超长寿命阶段50#车轴钢裂纹萌生于次表面夹杂.介绍了超声疲劳试验系统、工作原理及超声疲劳试样的设计.
Ultrasonic fatigue testing is an accelerated testing method with a frequency far beyond that of conventional fatigue experiment. The experimental results show that the fatigue strength at 20 kHz of 50# axle steel and 40Cr steel will diminish continuously as far as 1010 cycles. It is shown that 50# axle steel and 40Cr steel have no 'fatigue limit' as in the conventional fatigue curve. So the design of fatigue strength based on fatigue testing at 10 cycles is not adequate. The SEM shows that the fatigue crack propagation initiates at the subsurface inclusions in the regime of N > 107. Testing system of ultrasonic fatigue, operating principle and design of fatigue specimens axe described in this paper.
出处
《力学与实践》
CSCD
北大核心
2004年第6期25-29,共5页
Mechanics in Engineering
基金
四川省应用基础研究基金项目(02GY029-028)
铁道部科技研究开发计划项目(2001J016)
西南交通大学科学研究基金项目(2003B19)资助.
