Experimental and numerical study on high-cycle fatigue performance of austenitic stainless steel with pre-charged hydrogen

Abstract

High-cycle fatigue performance is one of the crucial issues for hydrogen diaphragm compressors, as hydrogen embrittlement affects the components in a high pressure hydrogen environment. In this study, the high-cycle fatigue response of MP7, a novel material of austenitic stainless steel designed for hydrogen diaphragm compressors, is investigated by tests and by numerical ways using the Crystal Plasticity Finite Element Method (CPFEM). The uniaxial tensile tests and fatigue tests are carried out on MP7 specimens with different levels of pre-charged hydrogen. The analysis indicates that, even for MP7 with the improved hydrogen resistance performance, both the ductility and the fatigue limit are still affected by the pre-charged hydrogen in a considerable way. Based on the principles of crystal plasticity theory, a CPFEM model is established and a fatigue life prediction model for austenitic stainless steel with pre-charged hydrogen is proposed. This model successfully predicts the fatigue life under different hydrogen contents and stress amplitudes, and the predicted fatigue lives are well-fitted to S-N curves within a two-fold error band.