Hydrogen in pipeline steels: Recent advances in characterization and embrittlement mitigation

Hydrogen is a carbon-free fuel that can facilitate the progress of achieving net-zero emission. The use of the existing natural gas pipelines for hydrogen transport is an essential strategy to reduce the investment required for hydrogen distribution. However, gas transmission pipelines are generally comprised of steels that are susceptible to hydrogen embrittlement (HE). The failure of steel pipes can result in hydrogen leakage, which could lead to serious incidents. This review article aims to provide an overview of HE-related problems in pipeline steels, with specific emphasis on hydrogen behaviors, hydrogen embrittlement and related characterizations, and mitigation strategies.