Very High-Cycle Fatigue Properties and Residual Stress Relaxation of Micro-shot-Peened EA4T Axle Steel
Very High-Cycle Fatigue Properties and Residual Stress Relaxation of Micro-shot-Peened EA4T Axle Steel
复制标题
微喷丸 EA4T 车轴钢的超高周疲劳性能和残余应力松弛
DOI：
10.1007/s11665-019-04371-x
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发表时间：
2019
影响因子：
2.3
通讯作者：
Li Xing
中科院分区：
文献类型：
--
作者：
Zhang Jinxin;Zhang Jiwang;Yang Bing;Li Xing
采用直径为50 μm的钢球和陶瓷球对EA4T合金铁路轴钢进行了喷丸处理，对未喷丸和喷丸处理后的试样进行了109次疲劳试验。研究了复合材料的疲劳性能和表面压缩残余应力松弛过程。表面断裂观察结果表明，裂纹均起源于表面，且喷丸和未喷丸试样均具有常规的高周疲劳极限。与未喷丸（UP）试样相比，陶瓷喷丸（CSP）和钢喷丸（SSP）试样的疲劳极限分别提高了31%和28%。疲劳极限的提高与表面压残余应力（SCRS）和表面硬化层有关。分析了弛豫过程中的SCRS和全宽半最大值（FWHM）值。当应力幅值低于循环屈服强度时，SSP试件的残余应力在第一个加载周期内快速松弛后保持稳定，而CSP试件的残余应力在第一个加载周期内快速松弛后缓慢松弛，然后保持稳定。对于所有施加应力幅值大于循环屈服强度的SSP和CSP试样，残余应力在初始循环中迅速松弛，在第一次加载循环后保持稳定。
In this paper, EA4T alloy railway axle steel was shot peened with steel balls and ceramic balls with a diameter of 50 μm, and 109-cycle fatigue tests of unpeened and peened specimens were carried out. The fatigue properties and the surface compression residual stress relaxation processes were investigated. The results of surface fracture observation indicated that all the cracks initiated from the surface, and both peened and unpeened specimens have conventional fatigue limits in the very high-cycle fatigue regime. Moreover, compared with unpeened (UP) specimens, the fatigue limits were improved by 31 and 28% for ceramic shot-peened (CSP) and steel shot-peened (SSP) specimens, respectively. The improvement of fatigue limit is related to the surface compressive residual stresses (SCRS) and the surface-hardened layer. The SCRS and full-width half-maximum (FWHM) values during the relaxation processes have been analyzed. At stress amplitudes lower than the cyclic yield strength, the residual stress of SSP specimens relaxed quickly in the first loading cycle and then remained stable, while the residual stress of CSP specimens relaxed quickly in the first loading cycle and relaxed slowly afterward, then remained stable. For all SSP and CSP specimens with applied stress amplitudes larger than the cyclic yield strength, the residual stress relaxed quickly in the initial cycles, and then remained stable after the first loading cycle.