SAF 2707HD旋转弯曲疲劳性能

针对SAF 2707HD双相不锈钢进行旋转弯曲疲劳实验.利用升降法计算得到疲劳极限,根据实验数据绘制应力-疲劳寿命(S-N)曲线,再利用扫描电子显微镜(SEM)对试样疲劳断口进行观察,分析了疲劳裂纹源的类型和断裂机制.统计数据表明:由于试样表面裂纹源引起的断裂基本发生在10⁵次循环或之内,而由于内部裂纹源引起的断裂基本发生在10⁶次循环,相差近一个数量级.为此利用有限元软件进行了疲劳寿命计算,预测结果与实验所得S-N曲线进行对比,确认了疲劳寿命分析的可靠性.

Study on SAF 2707HD fatigue performance in rotating bending

The rotational bending fatigue test of SAF 2707HD duplex stainless steel was carried out. The fatigue limit is determined by the up-and-down method, and the stress-lifetime (S-N) curve is hence drawn according to the experimental data. The fatigue fracture surface of the specimen is observed by scanning electron microscope (SEM), and the type of fatigue crack initiation and the corresponding fracture mechanism are analyzed respectively. Statistical data show that the fracture caused by crack origins on the surface of the specimen occurs basically at or within in 10⁵ cycles, while the fracture caused by internal crack origins occurs basically at about 10⁶ cycles, with a difference of nearly one order of magnitude. For this reason, the fatigue life is then predicted by using the finite element software. All predicted results are compared with the experimental S-N curve, which confirms the reliability of our fatigue life analysis.