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借助金相显微镜、X射线衍射仪对超声波冲击加工与传统抛光后试样表层组织性能进行对比分析,研究超声波冲击加工对30Cr Mn Si Ni2A疲劳寿命的影响。结果表明,经超声冲击后,试样表层组织变得更加细密从而阻止裂纹在表面萌生,形成更高的残余压应力减缓了裂纹扩展速率,使得1200 MPa下30Cr Mn Si Ni2A钢试样的疲劳寿命较传统抛光下的试样增加了23.5%。
By means of metallographic microscope and X-ray diffractometer, the microstructures of the surface of the 30Cr Mn Si Ni2A alloy after ultrasonic impact machining were compared with that of the conventional polished steel. The effects of ultrasonic impact machining on the fatigue life of 30Cr Mn Si Ni2A were studied. The results show that the surface microstructure of the sample is more finely cracked by ultrasonic impact, which prevents the initiation of cracks on the surface and the higher residual compressive stress slows down the crack growth rate, so that the fatigue life of 30Cr Mn Si Ni2A steel at 1200 MPa Compared with the traditional polished sample increased by 23.5%.