Estimation of creep crack growth properties using circumferential notched round bar specimen for 12CrWCoB rotor steel

Je Chang Ha, Joon Hyun Lee, Tabuchi Masaaki, A. Toshimitsu Yokobori

    Research output: Contribution to journalArticlepeer-review

    Abstract

    Most heat resisting materials in structural components are used under multi-axial stress conditions and under such conditions ductile materials often exhibit brittle manner and low creep ductility at elevated temperature. Creep crack initiation and growth properties are also affected by multi-axial stress and it is important to evaluate these effects when laboratory data are applied to structural components. Creep crack growth tests using circumferential notched round bar specimens are a simple method to investigate multi-axial stress effects without using complicated test facilities. Creep crack growth tests have been performed using a 12CrWCoB turbine rotor steel. In order to investigate the effects of multi-axial stress on creep crack growth properties, the tests were conducted for various notch depths at 650°C. The circumferential notched round bar specimens showed brittle crack growth behaviour under multi-axial stress conditions. Creep crack growth rate was characterized in terms of the C* parameter. A 12CrWCoB turbine rotor steel has been tested using circumferential notched round bar specimens with different multi-axiality. Circumferential notched round bar specimens show increased brittle creep crack growth behaviour due to the multi-axial stress condition. Creep crack growth properties could be predicted by allowing for the decrease of creep ductility under multi-axial conditions.

    Original languageEnglish
    Pages (from-to)397-402
    Number of pages6
    JournalKey Engineering Materials
    Volume297-300 I
    DOIs
    Publication statusPublished - 2005 Jan 1

    Keywords

    • C* parameter
    • Circumferential notched round bar specimen
    • Creep crack growth
    • Creep ductility
    • Multi-axial stress condition

    ASJC Scopus subject areas

    • Materials Science(all)
    • Mechanics of Materials
    • Mechanical Engineering

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