Influence of Hydrogen Environment on Fatigue Fracture Morphology of X80 Pipeline Steel

The rapid development of hydrogen energy requires the use of natural gas infrastructure for hydrogen transportation. It is very important to study hydrogen-added natural gas transportation technology, which is a key way to rapidly develop coal-based gas and renewable energy. This study aims to study the influence of X80 pipeline steel's fatigue performance in hydrogen environment, and perform fatigue tests on notched round rod specimens under different hydrogen concentration. The experimental results show that hydrogen seriously affects the fatigue life of pipeline steel. After reaching a certain hydrogen concentration, as the hydrogen concentration continues to increase, the fatigue life decreases gradually. Combined with SEM analysis of fracture morphology, the decrease in the size and density of the dimples reduces the displacement amplitude, while the increase in the planar area increases the displacement during fatigue fracture due to accelerated crack propagation. From this study, we can know the influence of hydrogen concentration on the fracture morphology of pipeline steel, which provides an understanding of the effect of hydrogen on fatigue fracture morphology and a broader safety analysis.