Hydrogen is emerging as an essential energy carrier for ecological transition. However, its development requires the introduction of mechanical systems that enable it to be produced, transported, and stored efficiently and safely. Therefore, further research is needed to ensure the safety and sustainability of hydrogen machines. Hydrogen is introduced into materials in the working environment. This absorbed hydrogen is one of the major causes of reduced mechanical properties of materials, which leads to catastrophic failure in service. This effect of absorbed hydrogen, which causes failure of high-strength materials, is known as hydrogen embrittlement.

Many studies have been carried out to investigate the mechanisms of the reduction of fretting fatigue strengths in hydrogen gas. The objective of this study is to understand the influence of the presence of hydrogen in the test environment crack nucleation mechanisms under fretting solicitation. An austenitic stainless steel 304L has been chosen seeing how frequently it is used for the mechanical components for high pressure gas to withstand high pressure. Sphere-plane fretting tests were then carried out in a gas chamber that allowed us to reach hydrogen pressures up to 250 bar. The evolution of the crack length as a function of the tangential force was plotted for different hydrogen pressures. Different loading conditions were applied for each hydrogen pressure to obtain plots of the projected crack length as a function of tangential load amplitude.