钒对中碳非调质钢疲劳性能的影响

采用旋转弯曲疲劳实验研究了含钒的38MnVS钢与不含钒的38MnS钢在热锻态和退火态下的疲劳行为.结果表明,V元素主要通过析出强化和组织细化改善铁素体 珠光体型非调质钢的疲劳性能.在热锻态,V(C,N)呈细小弥散分布,与铁素体间具有特定位向关系,具有明显的析出强化和细化组织作用.铁索体的强化使得疲劳裂纹萌生和扩展的抗力提高,因而38MnVS钢的疲劳性能明显优于38MnS钢;在退火态,V(C,N)质点长大,与铁素体间失去共格关系,不再具有明显的析出强化作用,因而退火态38MnVS钢的疲劳性能明显低于热锻态,而与38MnS钢的疲劳性能相当.

Effect of Vanadium on the Fatigue Properties of Microalloyed Medium-carbon Steel

The fatigue properties of vanadium-microalloyed ferrite-pearlite steel 38MnVS and steel 38MnS at different states were studied by using rotating-bending fatigue test.The results show that vanadium can improve the fatigue properties of ferrite-pearlite steel mainly through precipitation strengthening and grain refining mechanism.TEM examination shows that in the as-hot forged state, the fine V(C,N)particles with about 4nm in diameter have specific orientation relationship with ferrite matrix and significant effect on precipitation strengthening and microstructure refinement.The strengthening effect of soft ferrite raised the slip band initiation stress and delayed crack initiation,the fatigue property of the as-hot forged steel 38MnVS is much higher than that of steel 38MnS.In the as-annealed state,the initial fine V(C,N)particles coarsen and are incoherent with ferrite matrix,and have little effect on precipitation strengthening.Therefore,the fatigue property of the as-annealed steel 38MnVS is lower than that of the as-hot forged and is comparable to that of the steel 38MnS.