he conditional fatigue crack initiation lifes have been measured using rectangle notched specimens ofsteel 20CrMnMo under four point bending loads and the fatigue crack initation behaviors have ben studiedby microanalysis.

• 本文用四点弯曲加载法测定了20CrMnMo钢矩形缺口试样的条件疲劳裂纹萌生寿命，并用微观分析研究了疲劳裂纹的萌生行为。