碳元素含量对钢锻件疲劳性能的影响

The effect of carbon element content on the fatigue properties of steel forgings

对不同碳元素含量的钢锻件进行疲劳试验,研究了碳元素含量对钢锻件疲劳性能的影响,并对其断裂机制和强化机制进行分析。结果表明:随着碳元素含量的增加,材料的疲劳强度逐渐增大;在相同应变水平下,碳元素质量分数为0.3%的试样疲劳寿命最长;试样表面的几何缺陷或非金属夹杂处萌生微裂纹,并在条状物区域平稳扩展,最终试样在快速剪切中迅速断裂;经高温回火后,材料中过饱和的碳元素几乎全部以碳化物的形式析出,以固溶强化的形式提高了其疲劳性能。

Fatigue tests were conducted on steel forgings with different carbon element contents to investigate the effect of carbon element content on the fatigue performance of steel forgings,and to analyze their fracture and strengthening mechanisms.The results show that as the carbon content increased,the fatigue strength of materials gradually increased.At the same strain level,the sample with a carbon element mass fraction of 0.3% had the longest fatigue life.Microcracks originated from geometric defects or non-metallic inclusions on the surface of the specimen,and propagated smoothly in the strip-shaped area.The specimen eventually fractured rapidly in rapid shear.After hightemperature tempering,almost all supersaturated carbon elements in the material precipitated in the form of carbides,which improved its fatigue performance in the form of solid solution strengthening.