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研究了30CrMnsiNi2A高强钢在恒幅载荷下的小裂纹起始特征和裂纹扩展特性试验结果表明，小裂纹起始于缺口表面初始缺陷（如夹杂或孔洞）处在应力比R＝0的恒幅载荷下，未显示小裂纹效应；在R＝－1的恒幅载荷下，则显示出小裂纹效应的存在利用裂纹闭合模型和微观结构缺陷作为初始裂纹尺寸的方法预测了小裂纹扩展速率和疲劳全寿命，预测值与实验值符合良好.
The experimental results of small crack initiation and crack propagation of 30CrMnsiNi2A high strength steel under constant amplitude load show that the small crack starts at the initial amplitude defect (such as inclusions or holes) at the notch surface with constant amplitude load with stress ratio R = 0 Under the constant amplitude load of R = -1, the existence of the small crack effect is revealed. Using the crack closure model and the microstructure defects as the initial crack size, the small crack growth rate and fatigue are predicted Life expectancy, predicted and experimental values in good agreement.