Cr-Mo-V系高强度钢的疲劳断裂行为  

Fatigue fracture behavior of high strength Cr-Mo-V steel

作　　者：惠卫军[1] 聂义宏[2] 付书红[2] 董瀚[1] 翁宇庆[2] 

机构地区：[1]先进钢铁流程及材料国家重点实验室,北京100081 [2]先进钢铁材料技术国家工程研究中心

出　　处：《材料热处理学报》2007年第5期37-41,共5页Transactions of Materials and Heat Treatment

基　　金：国家重点基础研究发展计划项目(973)(2004CB619104)

摘　　要：采用旋转弯曲疲劳和疲劳裂纹扩展实验研究一种新型Cr-Mo-V系高强度钢在不同回火温度下的疲劳破坏行为。结果表明,Cr-Mo-V系高强度钢的旋转弯曲疲劳极限σ-1与抗拉强度Rm的比值σ-1/Rm随回火温度的升高而增加。在相同的强度水平下,实验钢的疲劳极限高于商业42CrMo钢。对疲劳断口裂纹源的分析表明,实验钢的疲劳裂纹主要起源于钢中的非金属夹杂物。采用C-T试样测定疲劳裂纹扩展速率的实验结果表明,Cr-Mo-V系高强度钢疲劳裂纹扩展第二阶段的扩展速率随回火温度升高而有所降低。在1500 MPa强度水平下,实验钢的疲劳裂纹扩展速率低于42CrMo钢。Fatigue fracture behavior of newly developed Cr-Mo-V steel queched and tempered at different temperatures was investigated using rotating-bending fatigue test and fatigue crack growth （FCG） test. The results show that the ratio of fatigue limit σ-1 to tensile strength Rm of Cr- Mo-V steel increases with increasing tempering temperature. The fatigue limit of Cr-Mo-V steel is higher than that of commercial steel 42CrMo at same strength level. The examination of the fatigue fracture surface shows that most of the fatigue cracks initiates at surface/subsurface non-metallic inclusions. The FCG results show that the stage- Ⅱ fatigue crack propagation rate da/dN of Cr-Mo-V steel decreases with increasing tempering temperature and is lower than that of commercial steel 42CrMo at tensile strength about 1500MPa.

关 键 词：Cr-Mo—V系高强度钢 回火温度 疲劳极限 疲劳裂纹扩展速率 

分 类 号：TG142[一般工业技术—材料科学与工程] TG115[金属学及工艺—金属材料]