Effect of Niobium Alloying on the Corrosion Fatigue Properties of the Cr-Co-Ni-Mo Series of Ultra-high Strength Stainless Steels
In order to investigate the stress corrosion cracking behavior of ultra-high strength stainless steel,the influence of Nb microalloying on the corrosion fatigue properties of Cr-Co-Ni-Mo series ultra-high strength stainless steel was studied by OM,XRD,TEM and other testing methods in combination with corrosion fatigue test.The results show that the steel has stress corrosion sensitivity in 3.5%NaCl solution,and the stress corrosion cracking mechanism of the steel was a mixed mechanism involving hydrogen embrittlement and anodic dissolution.Niobium alloying improved the corrosion fa-tigue performance of the steel,that is,the corrosion fatigue strength of steel increases from 440 MPa to 495 MPa after add-ing 0.11%Nb.The main reason is that niobium alloying refined the grain size of steel,promoted the precipitation of irre-versible hydrogen trap of NbC in steel,and increased the amount of prior austenite grain boundaries,the proportion of low-angle grain boundaries,the number of Σ3 grain boundaries,and the volume fraction of austenite in steel.
Ultra-high Strength Stainless SteelsErosion FatigueMechanism of Stress Corrosion CrackingNbCAus-tenite
NETL
NSTL
万方数据
维普
