STP1191: Propagation Behavior of Small Cracks in 304 Stainless Steel Under Biaxial Low-Cycle Fatigue at Elevated Temperature

    Ogata, T
    Central Research Institute of Electric Power Industry, Tokyo,

    Nitta, A
    Central Research Institute of Electric Power Industry, Tokyo,

    Blass, JJ
    Oak Ridge National Laboratory, Oak Ridge, TN

    Pages: 13    Published: Jan 1993


    Abstract

    To investigate the initiation and propagation behavior of small cracks and the relationship between crack propagation and fatigue life, strain-controlled in-phase and 90° out-of-phase axial-torsional fatigue tests were conducted at 550°C, using tubular specimens of 304 stainless steel with and without surface notches. Each test was interrupted at frequent intervals to make a film replica of the outer surface of the specimen for examination with an optical microscope. Most of the fatigue life was spent in the propagation of small cracks less than 2 mm long. Regardless of loading conditions, the crack propagation rate correlated well with the equivalent shear strain range defined as a function of shear strain range and normal strain range on the plane of maximum shear strain range. The biaxial low-cycle fatigue life could be estimated from the relationship between the crack propagation rate and the equivalent shear strain range.

    Keywords:

    304 stainless steel, biaxial low-cycle fatigue, high temperature, crack initiation, crack propagation, fatigue life prediction


    Paper ID: STP24809S

    Committee/Subcommittee: E08.05

    DOI: 10.1520/STP24809S


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