Novel utilization method of strengthening phases for improving steam oxidation behavior of heat-resistant steels

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K05055
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26040:Structural materials and functional materials-related
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Ueda Mitsutoshi 東京工業大学, 物質理工学院, 准教授 (90376939)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 耐熱鋼 / 高温水蒸気酸化 / 添加元素 / 金属間化合物 / 析出強化相

Outline of Final Research Achievements

This study focuses on the effects of alloying elements and strengthening phases on steam oxidation behavior of heat resistant steels at elevated temperatures. Niobium and tungsten were selected as alloying elements and steam oxidation tests were conducted by using model Fe-Cr and Fe-Cr-Ni alloys with the alloying elements. There are two effects of alloying elements on steam oxidation behavior: the effect of solid solution and the effect of precipitation. As a results of two effects, alloying elements of niobium and tungsten contribute to improve steam oxidation resistance of the alloys.

Free Research Field

耐熱金属材料の高温酸化

Academic Significance and Societal Importance of the Research Achievements

本研究によって，耐熱鋼の高温強度向上を意図して添加されるNbやWなどの添加元素が，耐水蒸気酸化特性の向上に対して有効に働くことが明らかとなった。これまでに，表面の酸化に対してあまり考慮されてこなかった母材中の析出強化相が，母材の機械的特性のみならず耐環境特性の向上にも大きく貢献することが明らかとなった。本研究で得られた知見は，今後の耐熱鋼開発の指針に対して，大きな示唆を与えると考えられる。