Nitride-strengthened reduced activation ferritic/martensitic steels

Ping Hu, Wei Yan, Li-fen Deng, Wei Sha, Yiyin Shan, Ke Yang

    Research output: Contribution to journalArticlepeer-review

    19 Citations (Scopus)

    Abstract

    Two nitride-strengthened reduced activation ferritic/martensitic (RAFM) steels with different Mn contents were investigated. The experimental steels were designed based on the chemical composition of Eurofer 97 steel but the C content was reduced to an extremely low level. Microstructure observation and hardness tests showed that the steel with low Mn content (0.47 wt.%) could not obtain a full martensitic microstructure due to the inevitable δ-ferrite independent of cooling rate after soaking. This steel showed similar room temperature strength and higher strength at 600 °C, but lower impact toughness, compared with Eurofer 97 steel. Fractography of the Charpy impact specimen revealed that the low room temperature toughness should be related to the Ta-rich inclusions initiating the cleavage fracture. The larger amount of V-rich nitrides and more dissolved Cr in the matrix could be responsible for the strength being similar to Eurofer 97 steel. In the second steel developed from the first steel by increasing the Mn content from 0.47 wt.% to 3.73 wt.%, a microstructure of full martensite could be obtained.
    Original languageEnglish
    Pages (from-to)1632-1637
    Number of pages6
    JournalFusion Engineering and Design
    Volume85
    Issue number7-9
    Early online date04 Jun 2010
    DOIs
    Publication statusPublished - Dec 2010

    Keywords

    • RAFM steel
    • Nitride strengthened
    • δ-Ferrite
    • Mechanical property
    • Cleavage fracture

    ASJC Scopus subject areas

    • Nuclear Energy and Engineering
    • Materials Science(all)
    • Civil and Structural Engineering
    • Mechanical Engineering

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