中文摘要：

采用旋转弯曲疲劳试验研究了4137钻具钢的疲劳性能.用扫描电镜和能谱仪分析了疲劳断口.结果表明：4137钢的疲劳极限是645.92 MPa.在保证试件表面没有划痕的情况下疲劳裂纹源位于次表面的复杂氧化铝夹杂物处;并建立了最大夹杂物尺寸与疲劳强度之间的关系模型,利用Gumbel分布函数通过对最大夹杂物尺寸进行估算得出疲劳强度,并对比旋转弯曲疲劳试验所得出的疲劳强度,两者相差7.61%.

英文摘要：

Fatigue performance of 4137 drill steel was studied by rotary bending fatigue tests. The fatigue fracture was analyzed with EDS and SEM. Influences of inclusion size and position on fatigue fatigue life of 4137 drill steel were studied. The results show that the fatigue strength of the steelwas541. 87 MPa. Fatigue cracks originated from ellipsoidal and low plasticity alumina inclusions without scratches on the surface. Thecorrelations between fatigue strength and maximuminclusions sizes were found. The error between fatigue property based on Gumbel statistics model and experiment fatigue strengthwas 7. 61%.