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本文研究了60Si2Mn钢的马氏体形态、硬度以及环境介质对疲劳裂纹萌生及扩展的影响。试验结果表明,具有相同马氏体形态的试样,其疲劳裂纹扩展速率随硬度的降低而减小;板条马氏体组织比针状马氏体组织具有较高的疲劳裂纹萌生抗力和较低的裂纹扩展速率;在水中试验,疲劳裂纹萌生最快,裂纹扩展速率最大;在机油中试验,其影响比在水中轻,比在空气中明显。高硬度试样的疲劳断口以沿晶断裂为主,随硬度降低,断口逐渐过渡为穿晶准解理;在水中试验,断口的沿晶成分显著增加。
In this paper, the effects of martensite morphology, hardness and environment medium on fatigue crack initiation and propagation in 60Si2Mn steel were studied. The experimental results show that the fatigue crack growth rate of specimens with the same martensitic morphology decreases with the decrease of the hardness; the lath martensite has higher fatigue crack initiation resistance than the acicular martensite, Low crack propagation rate; in the water test, the fatigue crack initiation is the fastest, the crack propagation rate is the largest; in the oil test, the impact is lighter than in the water, more obvious than in the air. The fatigue fracture of the high hardness specimen is mainly intergranular fracture, with the decrease of hardness, the fracture gradually transits to the transcrystalline quasi cleavage. In the water test, the intergranular composition of the fracture increases significantly.