锻造用贝氏体型非调质钢的高周疲劳性能  

High-cycle fatigue property of microalloyed bainitic steel for hot forging

作　　者：胡芳忠[1,2] 惠卫军[1,2] 雍岐龙[1,2] 张英建[2] 陈思联[2] 

机构地区：[1]昆明理工大学材料科学与工程学院,云南昆明650093 [2]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：《金属热处理》2011年第11期14-19,共6页Heat Treatment of Metals

基　　金：国家科技支撑计划项目(2007BAE51B03)

摘　　要：利用旋转弯曲疲劳试验方法研究了新开发的一种锻造用贝氏体型非调质钢的高周疲劳性能,并与典型的钒微合金化的铁素体-珠光体型非调质钢F38MnVS和调质钢40Cr进行了对比。结果表明,开发的贝氏体型非调质钢具有细小均匀的粒状贝氏体组织,在锻态的疲劳极限比达到了调质钢40Cr水平,但在正火后的疲劳性能有所降低。与同样钒微合金化的铁素体+珠光体钢F38MnVS相比,具有粒状贝氏体组织的试验钢的疲劳极限比较低。对疲劳断口的分析表明,贝氏体钢的疲劳裂纹均起源于试样的基本表面,疲劳裂纹以准解理机制扩展。进一步裂纹扩展速率试验表明,贝氏体钢的疲劳裂纹扩展速率da/dN明显低于铁素体+珠光体型非调质钢F38MnVS。High-cycle fatigue property of a newly developed microalloyed bainitic steel for hot forging and ferrite-pearlite type microalloyed steel F38MnVS and quenched and tempered（QT） low alloy steel 40Cr for comparisons were studied using rotating-bending fatigue test.The results show that the developed steel has a fine granular bainitic structure and its fatigue limit ratio in as-forged condition is comparable to that of QT steel 40Cr,whereas is lower than that of ferrite-pearlite type.The fatigue property in as-normalized condition is slightly lower than that in as-forged condition.Further SEM examination of fatigue specimen fracture surfaces revealed that all the fatigue cracks initiated from specimen sub-surface and propagated in forms of quasi-cleavage.The fatigue crack growth rate da/dN of the developed bainitic steel is slower than that of F38MnVS steel.

关 键 词：贝氏体型非调质钢 非调质钢 高周疲劳性能 微观组织 疲劳裂纹萌生与扩展 

分 类 号：TG111.8[金属学及工艺—物理冶金] TG142[金属学及工艺—金属学]