Hydrogen embrittlement response of dual layer marine structural materials

• Main Author: Tan, Jin Jie
• Other Authors: Sridhar Idapalapati
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Mechanical engineering
• Online Access: https://hdl.handle.net/10356/172837
• Institution: Nanyang Technological University

The research centers on hydrogen embrittlement in API X 60 steel pipelines clad with corrosion-resistant alloy Inconel 625, commonly used in long-haul oil and gas transportation. The investigation involves subjecting dog bone samples to varying levels of plastic strain followed by hydrogen emission reactions, utilizing Scanning Electron Microscopy (SEM) to map hydrogen diffusion profiles. Results reveal a significant negative impact on mechanical properties, emphasizing increased brittleness induced by hydrogen charging and pre-straining. The study concludes that the operational life of hydrogen storage pipelines is more precarious than those used for natural gas, suggesting a necessary reduction in operational life by at least 20%. Future solutions, such as exploring stronger materials like Inconel 625 or alternative coatings, are proposed. However, the study acknowledges limitations due to time constraints, with only limited sets of prestrained samples tested and no Thermal Desorption Spectroscopy (TDS) conducted on prestrained samples.