本文研究喷丸时间与多次冲击弯曲抗力的关系。零部件喷丸只有接近或达到“饱和时间”,才能大幅度提高多冲抗力,起到强化效果。喷丸时间不足,将大大地降低强化效果。试验又揭示了“过饱和喷丸”并不恶化多冲抗力。通过对喷丸后试片的残余应力测定,指出残余压应力对受交变冲击应力的零件有提高冲击疲劳寿命的作用 This paper studies the relationship between shot peening time and multiple impact bending resistance. Only close to or reach the part of the “saturation time”, can greatly improve the multi-impact resistance, play to strengthen the effect. Shot peening time, will greatly reduce the strengthening effect. The experiment also revealed that “supersaturated shot peening” did not worsen the multi-impact resistance. By measuring the residual stress of the shot after shot peening, it is pointed out that the residual compressive stress has the effect on improving the impact fatigue life for the parts subjected to alternating impact stress