STP683: Tensile Property Correlations for Highly Irradiated 20 Percent Cold-Worked Type 316 Stainless Steel

    Fish, RL
    Senior engineer, advanced engineer, and manager, Mechanical Properties, Hanford Engineering Development Laboratory, Westinghouse Hanford Company, Richland, Wash.

    Cannon, NS
    Senior engineer, advanced engineer, and manager, Mechanical Properties, Hanford Engineering Development Laboratory, Westinghouse Hanford Company, Richland, Wash.

    Wire, GL
    Senior engineer, advanced engineer, and manager, Mechanical Properties, Hanford Engineering Development Laboratory, Westinghouse Hanford Company, Richland, Wash.

    Pages: 16    Published: Jan 1979


    Abstract

    Recent experiments on developmental fast-flux test facility (FFTF) cladding (20 percent cold-worked Type 316 stainless steel) have extended the data base to a fast neutron fluence of 8.4 × 1022 neutrons (n)/cm2 (E > 0.1 MeV). The specimens were irradiated in the experimental breeder reactor-II (EBR-II) at temperatures ranging from 371 to 816°C, although peak fluence levels were attained on specimens irradiated near 371 and 649°C only. Tension tests were performed at 232°C, near the irradiation temperature, and, in some cases, above the irradiation temperature. Test specimen strain rates ranged from 4 × 10 -5/s to 4 × 10-2/s.

    The data generated on cladding irradiated near 371 °C established that the low-temperature strength and ductility are fluence independent beyond about 5 × 1022 n/cm2 (E > 0.1 MeV). The strength behavior of the irradiated cladding at 538, 593, and 649 °C is essentially the same as exhibited by thermally aged developmental cladding at the same temperatures and times out of the reactor. Up to a fluence of ∼5 × 1022 n/cm2 (E > 0.1 MeV), the 538°C ductility values remain relatively fluence independent after an initial decrease. Higher temperature (593 and 649 °C) ductilities decrease continually with increasing fluence.

    Tensile parameter correlations were developed for the prediction of irradiation effects on the tensile properties of 20 percent cold-worked Type 316 stainless steel. These correlations are based on unirradiated tensile property correlations developed using Hart's equation-of-state approach. The basic premise is that the condition of plastic deformation of some materials such as 316 stainless steel can be characterized by a structure parameter (σ*) which describes the material's “hardness.” It is found that irradiation effects can be incorporated into this formulation by parameterizing the changes in σ* with irradiation temperature and fluence. The resulting correlations provide a description of strength and ductility over the temperature range of 371 to 871 °C and strain rates of 10-5 to 10 1/s.

    Keywords:

    irradiation, stainless steel, tensile strength, fast reactor, ductility, strain rate, correlations


    Paper ID: STP38181S

    Committee/Subcommittee: E10.07

    DOI: 10.1520/STP38181S


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