Hydrogen Embrittlement Mechanism in Fatigue Behavior of Austenitic and Martensitic Stainless Steels

In the present study, the influence of hydrogen on the fatigue behavior of the high strength martensitic stainless steel X3CrNiMo13-4 and the metastable austenitic stainless steels X2Crni19-11 with various nickel contents was examined in the low and high cycle fatigue regime. The focus of the investigations were the changes in the mechanisms of short crack propagation. Experiments in laboratory air with uncharged and precharged specimen and uncharged specimen in pressurized hydrogen were carried out. The aim of the ongoing investigation was to determine and quantitatively describe the predominant processes of hydrogen embrittlement and their influence on the short fatigue crack morphology and crack growth rate. In addition, simulations were carried out on the short fatigue crack growth, in order to develop a detailed insight into the hydrogen embrittlement mechanisms relevant for cyclic loading conditions. It was found that a lower nickel content and a higher martensite content of the samples led to a higher susceptibility to hydrogen embrittlement. In addition, crack propagation and crack path could be simulated well with the simulation model.