60Si2CrVA高强度弹簧钢的超高周疲劳破坏行为  

Very high cycle fatigue fracture behavior of high strength spring steel 60Si2CrVA

作　　者：赵海民[1] 惠卫军[1] 聂义宏[1] 翁宇庆[1] 董瀚[1] 

机构地区：[1]钢铁研究总院先进钢铁材料技术国家工程研究中心,北京100081

出　　处：《材料研究学报》2008年第5期526-532,共7页Chinese Journal of Materials Research

基　　金：国家重点基础研究发展规划2004CB619104资助项目~~

摘　　要：进行超声波疲劳和疲劳裂纹扩展速率实验,研究了3种60Si2CrVA弹簧钢的超高周疲劳破坏行为.结果表明,60Si2CrVA弹簧钢的超高周疲劳性能主要与其中夹杂物的尺寸有关,即随着夹杂物尺寸的减小,钢的疲劳寿命和疲劳强度均逐渐提高.对于内部夹杂物引起的疲劳破坏,在低应力幅、高循环周次(约大于10~6 cyc)条件下,在夹杂物周围的鱼眼处往往存在粗糙的粒状区域(GBF).对于A-60钢,随着疲劳源夹杂物处应力场强度因子幅的减小,疲劳寿命增加;而GBF处的应力场强度因子幅并不随疲劳寿命变化而变化,基本为一常数(平均值为4.6 MPa·m^(1/2)),与疲劳裂纹扩展门槛值(4.3 MPa·m^(1/2))接近.Very high cycle fatigue fracture behaviors of three heats commercial spring steels 60Si2CrVA were studied by using ultrasonic fatigue test and fatigue crack propagation rate test. Ex- perimental results show that significant difference of the very high cycle fatigue properties of the tested steels were mainly caused by the difference of inclusion size. That is, both fatigue life and fatigue strength increase with decreasing the inclusion size. In the case of internal inclusion-induced fractures at cycles beyond 1×10^6, a fish-eye area was usually seen on the fracture surface, and inclusion was usually observed inside the fish-eye and a granular bright facet （GBF） was found in the vicinity around the inclusion. Further investigation of heat A-50 reveals that the stress intensity factor range at crack initiation site of inclusion has the trend to decrease gradually with increasing the number of cycles to failure Nf, while that at crack initiation site of GBF is almost constant with Nf with an average value of about 4.6 MPa·m^1/2, which is very close to the fatigue crack propagation threshold of about 4.3 MPa·m^1/2.

关 键 词：金属材料 60Si2CrVA弹簧钢 超高周疲劳 疲劳裂纹扩展速率 非金属夹杂物 

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]