32Cr3MoVE轴承钢旋弯疲劳特性及裂纹萌生扩展行为

摘要：采用光滑漏斗状试样对32Cr3MoVE轴承钢进行旋转弯曲疲劳测试，研究了32Cr3MoVE轴承钢旋转弯曲疲劳性能及裂纹萌生扩展行为。采用升降法测得其疲劳极限为860MPa，疲劳断口SEM观察并统计破断试样结果表明：疲劳破坏68.7%是由于非金属夹杂起裂，18.8%由表面加工缺陷起裂，125%为表面粗糙度起裂。当加载应力低于980MPa时，疲劳断裂主要是由于内部非金属夹杂引起的，高于980MPa时，疲劳断裂主要是由于表面粗糙度引起的。表面加工缺陷和表面粗糙度引起的最大应力强度因子分别为3.05和2.97MPa·m1/2，容易引发疲劳裂纹。非金属夹杂物尺寸在5.30～5.90μm范围内，局部应力从859.35MPa升至977.75MPa时，疲劳寿命从1.96×105降低到1.58×105；非金属夹杂物局部应力在840～900MPa范围内，夹杂物尺寸从2.28μm升至5.83μm时，疲劳寿命从1.10×106降低到1.96×105。

Rotary bending fatigue characteristics and crack initiation and propagation behavior of 32Cr3MoVE bearing steel

The rotating bending fatigue test of 32Cr3MoVE bearing steel was carried out with a smooth funnel shaped specimen, and the rotational bending fatigue characteristics and crack initiation and propagation behavior of 32Cr3MoVE bearing steel were studied. The fatigue limit measured by the lifting method is 860MPa, Fatigue fractures were observed using SEM and statistical breaking tests were performed that 68.7% of fatigue failure was caused by non metallic, 18.8% by surface machining defects, and 12.5% by surface roughness. When the loading stress is lower than 980MPa, the fatigue fracture is mainly caused by the internal non metallic inclusions. When the loading stress is higher than 980MPa, the fatigue fracture is mainly caused by surface defects. The maximum stress intensity factors caused by surface machining defects and surface roughness are 3.05MPa·m1/2 and 2.97MPa·m1/2, which are easy to cause fatigue cracks. When the size of non metallic inclusions is in the range of 5.30-5.90μm and the local stress increases from 859.35MPa to 977.75MPa, the fatigue life decreases from 1.96×105 to 1.58×105. When the local stress of non metallic inclusions is in the range of 840-900MPa, and the inclusion size increases from 2.28μm to 5.83μm, the fatigue life decreases from 1.10×106 to 1.96×105.