Quantitative Evaluation of Mechanical Properties of Hydrogen Transmission Pipelines Based on Weak Magnetic Detection

With the rapid development of the hydrogen energy industry, long-distance hydrogen transportation based on natural gas pipelines has emerged as a crucial technique. However, exposure to a hydrogen environment can lead to the degradation of pipeline mechanical properties, resulting in hydrogen corrosion, which may increase the risk of pipeline failure. Consequently, it is crucial to evaluate the mechanical properties of pipeline steel under a hydrogen environment to ensure pipeline safety. In this paper, hydrogen corrosion experiments for X80 pipeline steel are carried out with varying hydrogen charging times. Through tensile fracture experiments and weak magnetic detection technology, the effects of defects and hydrogen concentration on the stress-strain characteristics and magnetic signal characteristics of X80 steel are investigated. Based on the correlation level, the quantitative relationships between hydrogen concentration, magnetic signal characteristics, and mechanical properties are established, and the sparrow search algorithm (SSA) is utilized to modify these quantitative relationships. The results indicate that with the increase in defect depth, the magnetic signal characteristics gradually increase. With the increase in defect diameter, these parameters gradually decrease. The modified quantitative relationships provide the accurate assessment of the ultimate bearing capacity, yield strength, and ultimate tensile strength, with average relative errors of 7.91%, 3.15%, and 2.04%, respectively. This study provides a theoretical basis for ensuring the safe transportation of hydrogen transmission pipelines.