Objective Injecting hydrogen into natural gas pipelines for mixed transportation is one effective way to reduce carbon emissions. However, with the injection of hydrogen, issues such as hydrogen-induced cracking and hydrogen-assisted crack propagation, resulting from the infiltration of hydrogen atoms into the pipeline material, affect the mechanical property service life of the pipelines.

Method This study examined the structural changes and stress-strain analysis of the α-Fe model under various hydrogen atom mole fraction and temperature conditions using molecular simulation methods.

Result The simulation results have indicated that the infiltration of hydrogen atoms has a significant impact on the material's performance. At a 5% hydrogen atom mole fraction compared to 0, the elastic limit decreased by 21.981%, and the Young's modulus decreased by 29.376%. The change in the model lattice structure was the fundamental cause of the deterioration of mechanical properties, as well as the reduction in the elastic limit and Young's modulus of the α-Fe model. The temperature change had a relatively small impact on the material after hydrogen infiltration. At different temperatures, the change rate of tensile strength and Young's modulus of the α-Fe model were both lower than 5%.

Conclusion Based on the simulation results of the performance changes of defect-containing materials after hydrogen infiltration, the impact rule of hydrogen atom mole fraction and temperatures on the performance of defect-containing materials is clarified, providing a reference for future hydrogen blending in natural gas pipelines.