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利用旋转弯曲疲劳实验,研究了3种商业生产的60Si2CrVA弹簧钢的高周疲劳破坏行为。结果表明,虽然实验料的氧含量相同,但由于钢中夹杂物尺寸的差异,使其高周疲劳性能存在明显差异。随着夹杂物尺寸的减小,实验料的疲劳寿命和疲劳强度均逐渐提高。夹杂物最为粗大的D-60料(平均夹杂物尺寸фin≈44.4μm),疲劳S-N曲线连续降低,疲劳断裂主要起源于钢中的粗大夹杂物,传统的疲劳极限消失;夹杂物最为细小的A-60料(фin≈15.4μm),疲劳断裂主要起源于表面基体,存在传统的疲劳极限。对于在低应力幅、高循环周次(约大于106)下,内部夹杂物引起的疲劳破坏,在夹杂物周围往往存在粗糙的粒状区域。
Using high-cycle fatigue test, the high-cycle fatigue failure behavior of three commercial 60Si2CrVA spring steels was studied. The results show that although the oxygen content of the test material is the same, there is a significant difference in the high-cycle fatigue properties due to the difference in the size of inclusions in the steel. As the inclusion size decreases, the fatigue life and fatigue strength of the experimental materials are gradually increased. The most coarse inclusions D-60 material (mean inclusion size фin≈44.4μm), the continuous decrease of the fatigue SN curve, fatigue fracture mainly originated in the coarse inclusions in steel, the traditional fatigue limit disappears; inclusions the most small A -60 material (фin≈15.4μm), fatigue fracture mainly originated from the surface of the matrix, there is the traditional fatigue limit. For the fatigue damage caused by the internal inclusions under the low stress amplitude and the high cycle (more than about 106), there are often rough granular areas around the inclusions.