Effect of Hydrogen Blending Ratio on the Hydrogen Embrittlement Sensitivity of X60 Pipeline Steel

摘要

Blending a certain proportion of h ydrogen into natural gas and transporting it through existing pipelines is the most cost -effective method for long -distance hydrogen transportation. However, the evaluation of the adaptability of hydrogen - blended natural gas pipelines is not yet fully deve loped. This study investigates the hydrogen embrittlement behavior of X60 steel under hydrogen blending ratios of 0–30% at 12 MPa using slow strain rate tensile (SSRT) tests combined with SEM analysis. In-situ high-pressure gas-phase hydrogen permeation tests were conducted to accurately determine subsurface hydrogen concentrations under different hydrogen blending ratios. The results indicate that as the hydrogen blending ratio increased from 10% to 20%, the subsurface hydrogen concentration, plasticity lo ss, and hydrogen embrittlement sensitivity significantly increased. Additionally, a positive correlation was observed between subsurface hydrogen concentration and hydrogen embrittlement index. Based on the hydrogen permeation, SSRT results, and fracture m orphology analysis, the safe critical range for the operation of X60 hydrogen-blended natural gas pipelines was determined to be a hydrogen blending ratio of 10%.