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对截面为3 mm×3mm的16Mn钢试件在空气和3.5%NaCl溶液中分别进行疲劳试验,获此外,研究发现在空气中的弯曲疲劳极限σ?1与抗拉强度σb之间的关系为σ-1≈0.5σb。据此并得了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,3.5%NaCl腐蚀溶液使16Mn钢的疲劳强度显著降低;在空气中疲劳试样只有一个萌生于试样表面基体的裂纹源,而在3.5%NaCl溶液中一般有多个裂纹源,而大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,而在3.5%NaCl溶液中的腐蚀疲劳则以沿晶开裂等脆性特征为主。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,误差在10%以内。本文研究结果可为16Mn钢结构的设计和使用提供依据。
The fatigue tests of 16Mn steel with 3mm × 3mm section in air and 3.5% NaCl solution were carried out respectively. In addition, it was found that the relationship between the bending fatigue limit σ 1 and the tensile strength σb in air was σ-1 ≈ 0.5σb. Based on this, the S-N curve was obtained and the surface of the fatigue specimen and the fracture morphology were observed. The results show that the fatigue strength of 16Mn steel is significantly lower than that of air in 3.5% NaCl solution. There is only one crack initiation source in the air, which is originated from the surface of the sample, but is generally found in 3.5% NaCl solution However, most of the cracks originated in the pits. The fatigue crack growth in the air was dominated by fatigue and the corrosion fatigue in 3.5% NaCl solution was dominated by the brittle features such as the cleavage of the intergranular. The fatigue limit in the air was predicted, the predicted value is in good agreement with the experimental value, and the error is within 10%. The results of this paper can provide the basis for the design and use of 16Mn steel structure.