Research Progress and Prospects on Hydrogen Damage in Welds of Hydrogen-Blended Natural Gas Pipelines

Hydrogen energy represents a crucial pathway towards achieving carbon neutrality and is a pivotal facet of future strategic emerging industries. The safe and efficient transportation of hydrogen is a key link in the entire chain development of the hydrogen energy industry's "production, storage, and transportation". Mixing hydrogen into natural gas pipelines for transportation is the potential best way to achieve large-scale, long-distance, safe, and efficient hydrogen transportation. Welds are identified as the vulnerable points in natural gas pipelines, and compatibility between hydrogen-doped natural gas and existing pipeline welds is a critical technical challenge that affects the global-scale transportation of hydrogen energy. Therefore, this article systematically discusses the construction and weld characteristics of hydrogen-doped natural gas pipelines, the research status of hydrogen damage mechanism, and mechanical property strengthening methods of hydrogen-doped natural gas pipeline welds, and points out the future development direction of hydrogen damage mechanism research in hydrogen-doped natural gas pipeline welds. The research results show that: (1) Currently, there is a need for comprehensive research on the degradation of mechanical properties in welds made from typical pipe materials on a global scale. It is imperative to systematically elucidate the mechanism of mechanical property degradation due to conventional and hydrogen-induced damage in welds of high-pressure hydrogen-doped natural gas pipelines worldwide. (2) The deterioration of mechanical properties in welds of hydrogen-doped natural gas pipelines is influenced by various components, including hydrogen, carbon dioxide, and nitrogen. It is necessary to reveal the mechanism of mechanical property deterioration of pipeline welds under the joint participation of multiple damage mechanisms under multi-component gas conditions. (3) Establishing a fundamental database of mechanical properties for typical pipeline steel materials under hydrogen-doped natural gas conditions globally is imperative, to form a method for strengthening the mechanical properties of typical high-pressure hydrogen-doped natural gas pipeline welds. (4) It is essential to promptly develop relevant standards for hydrogen blending transportation, welding technology, as well as weld evaluation, testing, and repair procedures for natural gas pipelines.