Development of a hydrogen-resistant austenitic steel

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K04178
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 18010:Mechanics of materials and materials-related
• Research Institution: Yamaguchi University
• Principal Investigator: MACADRE Arnaud 山口大学, 大学院創成科学研究科, 准教授 (20635891)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 水素脆化 / 鉄鋼材料 / オーステナイト / 相変態 / 窒素添加 / 組織微細化

Outline of Final Research Achievements

This research aimed at developing a hydrogen-compatible metastable austenitic stainless steel. The base material was the metastable SUS304 which is not hydrogen compatible (hydrogen embrittlement occurs). First, the optimum nitrogen content to be added was investigated; it was followed by microstructure refinement: both led to hydrogen compatibility similar to hydrogen-compatible stable austenitic stainless steels. The strength level was also higher than hydrogen-compatible stable austenitic stainless steels (yield stress increasing from 200MPa to 470MPa). The combination of nitrogen addition and microstructure refinement led to the realization of high-strength, hydrogen-compatible, low-nickel austenitic stainless steel.

Free Research Field

材料工学

Academic Significance and Societal Importance of the Research Achievements

水素適合性のための添加窒素量は0.3mass%とされていたが、初めて0.3mass%以上でも組織微細化を組み合わせれば、水素脆化を妨げることを示した。耐水素脆性合金のデザインのために重要な知識である。
また低ニッケルオーステナイト系ステンレス鋼（SUS304）でも応用できる方法（高温窒素ガスによる窒素添加＋冷間圧延と再結晶熱処理）により水素適合性と強度増加を同時に得ることができることを示した。その結果から、水素設備に利用できる材料が増え、水素社会の実現に繋がる。