本文研究了38CrMoAlA和30CrMnSiA两种钢中所含夹杂物对疲劳性能的影响。研究结 果表明：在夹杂物含量基本相同的条件下，夹杂物的大小、形状及分布特徴对疲劳寿命具有明 显的影响，夹杂物的颗粒大小直接支配着裂纹的成核与扩展，当夹杂物的平均直径大于40Hm吋, 由夹杂物引起疲劳失效的比率可达95%以上.因此，在控制夹杂物含S的基础上，通过减小夹.杂物颗粒尺寸和改变不利的几何形状及分布，.可减缓夹杂物对疲劳性能的有害影响。

The present paper has investigated effect which the inclusion in 38CrMoA1A and 30CrMnSiA steels on the fatigue properties the present study has shown that the inclusion sizes、shapes and distributions in steels have a marked effect on the fatigue properties under same inclusion content.The fatigue crack nucleation and propagation are controlled directly by inclusion particle sizes.As the mean diameter of inclusion particles is larger than 40jim, the frequency of the fatigue failures caused by non-metallic inclusions will be above 95%.On the basis of controling inclusion cotent, the fatigue properties can be impoved by decreasing the inclusion particles size and changing the unfavorable geometry shapes and distribution in steels.