低合金钢在不同条件下的疲劳行为

THE FATIGUE BEHAVIOR OF LOW ALLOY STEEL UNDER DIFFERENT CONDITION

  • 摘要: 在空气和腐蚀介质中对低合金钢分别的进行疲劳试验,获得了S-N曲线,并对疲劳试样表面和断口形貌进行了观察。结果表明:与空气相比,腐蚀介质使低合金钢的疲劳强度显著降低;空气中疲劳试样只有一个萌生于试样表面基体的裂纹源,而腐蚀介质中的疲劳试样一般有多个裂纹源,多数裂纹源均萌生于点蚀坑;空气中疲劳裂纹扩展区以疲劳辉纹为主,而腐蚀疲劳则以沿晶开裂等脆性特征为主;此外还对空气中的疲劳极限进行了预测,预测值与试验值比较吻合

     

    Abstract: The fatigue behavior of Low alloy steel in air and corrosion medium was studied by the fatigue tests. The S-N curves were obtained and the observations of flat surfaces and fatigue fractographs have been made. The results showed that the fatigue strength of Low alloy steel in corrosion medium was much lower than that in air. Fatigue cracks in air were initiated from the matrix of surface, while most of fatigue cracks in corrosion medium were initiated from pits. The typical feature of the fatigue crack propagation region in air was fatigue striations, while that in corrosion medium was intergranular crack characteristic. The fatigue limit in air could be predicted by empirical equation. The predicted fatigue limit was agreeable to the experimental fatigue limit.

     

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