Study On Bending Fatigue Behavior Of Cr-Mn Austenite Stainless Steel

Cr-Mn austenitic stainless steel which has excellent corrosion resistance,low magnetization and good comprehensive mechanical properties is widely used in transportation,aviation,electricity and other important areas.But different degrees of fatigue damage will inevitably occur under the condition of complex loading cycle,which will finally lead to the failure of material.The fatigue damage of material under low load is not easy to detect and often cause serious consequence,so it's important to study the fatigue behavior of material under cyclic loading.This article combined four-point-bending fatigue test and the finite element method(FEM)to study the fatigue behavior of Cr-Mn austenitic stainless steel.The stress and fatigue life distributions of fatigue sample were determined.The initiation,propagation and fatigue mechanism of Cr-Mn austenitic steel in different stress levels were revealed.The FEM results showed that stress distributions between the two loading rollers were different when sample sizes were not the same.Reasonable size range of the samples with uniform stress distribution were determined by analyzing the stress cloud and experimental value of the specimen under different sizes.The reasonable sample size was selected to simulate the fatigue life and conduct experimental study.The fatigue life simulation results showed that the fatigue life was the shortest in the middle of the two loading rollers where the fatigue fracture occured.The experimental results showed that most of the cracks were initiated at the {111}<110> primary slip bands,especially within coarse grains.The direction of the crack extension was perpendicular to the principal stress and usually only a small amount of initiated cracks(1-2 cracks)could lead to the final failure of the samples.The cracks were deflected at grain boundaries,which effectively arrested the propagation of most cracks.The experimental results was consistent with FEM simulation results by analysing the simulation of fatigue life,experimental value and fatigue crack.It is obviously that the FEM can accurately analyse the stress state and predict the fatigue life of material.Finite element analysis is a new practical and effective method to study fatigue behavior and predict the fatigue life of material.The research on the fatigue performance and the mechanism of fatigue damage of Cr-Mn austenitic stainless steel can provide theory guidance and experimental support for engineering practice,and reduce the loss caused by fatigue damage.