Preface to the Special Issue on “Toward Suppression of Hydrogen Absorption and Hydrogen Embrittlement for Steels”

Study

It is well known that steel materials supported the whole society as useful structural materials and evolved to exhibit high strength for the construction of large-scale structures, such as high-rise buildings and long-span bridges in the 20th century. In the 21st century, demand for higher-strength steels has increased from the viewpoints of resource saving, energy saving, and environmental conservation. For example, automobile industry has great interest in higher-strength steels to achieve weight reduction of automobiles while retaining strength. Therefore, higher-strength steels are being actively developed. However, it is also known that high-strength steels suffer from hydrogen embrittlement in steel-corrosive environments, including humid atmospheres. Since this phenomenon was recognized for a long time, a number of researchers have successfully classified its mechanical and microstructural features, and some researchers have proposed precious mechanisms of hydrogen embrittlement. Although continuous efforts have been made and abundant results have been accumulated so far, high-strength steels still suffer from the embrittlement. Recently, the understanding and countermeasures to hydrogen embrittlement of high-strength steels has become an important topic worldwide. As a result, many international and domestic conferences have been held, and active discussions have taken place in the conferences. The Iron and Steel Institute of Japan (ISIJ) has also expressed great interest in understanding and suppressing hydrogen embrittlement of high-strength steels, and emphasized its importance on the road map of the institute. Accordingly, ISIJ has continuously supported a lot of groups researching hydrogen embrittlement of high-strength steels. In the research groups, efforts to understand and suppress the embrittlement have been pursued from mechanical and microstructural viewpoints. In addition, some research groups were activated from the viewpoints of hydrogen absorption induced by corrosion as well as of noble techniques for precise detection of hydrogen distribution through the steels. This special issue on “Toward Suppression of Hydrogen Absorption and Hydrogen Embrittlement for Steels” is a collection of the current and cutting-edge research articles regarding hydrogen embrittlement by the groups in ISIJ. The issue will serve a valuable resource for understanding hydrogen embrittlement. Finally, I would like to express my gratitude to all the members of the forum “Fundamental factors and practical issues of hydrogen embrittlement” and the research group “Corrosion-Induced Hydrogen Absorption to Steels” for their contributions, and to the entire editorial staff who supported the publication of this special issue.