Abstract
To facilitate the deployment of hydrogen-based technologies, it is important to develop strategies for the safe and cost-effective storage and transportation of H. Notable approaches include repurposing existing natural gas pipelines for the transportation of hydrogen (or hydrogen/natural gas blends) and utilizing higher strength pipeline steels to establish new networks for hydrogen transportation. Furthermore, the development and application of lower-cost, high-performance steels are critical for the extensive implementation of hydrogen refueling infrastructure. These materials must demonstrate high resistance to hydrogen embrittlement to ensure the efficiency and reliability of hydrogen storage and transportation systems. This paper highlights recent advances in the design, characterization, and assessment of various steel grades and microstructures developed for hydrogen service applications. High strength ferritic steels, including API X65 and X70 grades, are being investigated to evaluate their applicability in high-pressure hydrogen transportation. Recent research has focused on understanding the influence of base metal microconstituents and weld heat affected zones to evaluate microstructural characteristics that influence hydrogen embrittlement. Additionally, a new family of high manganese austenitic and duplex steels has been designed through thermodynamic modeling and calculations, providing a more economical alloy alternative to commonly used stainless steels that contain expensive alloying elements like nickel and chromium. Several thermomechanical processing strategies are applied to these alloys to enhance the hydrogen embrittlement resistance and strength. Advanced characterization techniques, including in-situ neutron diffraction, combined with in-situ mechanical testing in electrochemical and gaseous hydrogen environments, are employed to investigate the influence of hydrogen on deformation and embrittlement mechanisms in these steels.