Assessment of Hydrogen Embrittlement of Operated Pipe Steel Using the J-Integral Method

Fracture due to hydrogen embrittlement is a major concern for the reliability and safety of hydrogen transportation via gas pipelines. Pipe steels are characterized by high plasticity, therefore, methods of nonlinear fracture mechanics, including the J-integral method, are preferred for determining the fracture toughness. The influence of preliminary electrochemical hydrogen charging under a moderate mode on fracture toughness of API 5L X67 steel in the as-delivered and 34-year operated on the gas main pipeline conditions was studied. A methodological feature of the experiments is the use of different rates of mechanical loading of specimens with cracks. The influence of the long-term operation of steel on its resistance to brittle fracture is revealed, depending on the test conditions.