This study aims to explore the structural strength deterioration mechanism of pipelines with corrosion defects in hydrogen-blended environments.

Based on the experimental data, an analysis is made of the load bearing performance of X52 steel under different levels of hydrogen blending , and the structural strength failure mechanism of an X52 hydrogen-blended natural gas pipeline under different corrosion defects is described using the nonlinear finite element method.

When the hydrogen blend level increases to 50.0%, under a combined load, the pipeline reaches minimum displacement failure at 2.58 mm, and the structural toughness deteriorates to a greater degree; at a hydrogen blend level of 25.0%, the defect depth is greater and the degree of structural failure more serious; comparing square and circular defects, the maximum stress of the square defects is higher than that of the circular defects.

The material property-based defective pipeline model can realize the assessment of the structural bearing capacity deterioration of natural gas pipelines under different hydrogen-blending conditions, providing engineering suggestions for the design and health monitoring of new energy pipelines.